The M's picture is excellent, in the same league with more expensive sets like the Samsung Q7 and Sony X950G in my side-by-side comparisons. Each has its strengths and weaknesses, but in terms of pure image quality it's tough to justify spending more for one of those sets over the Vizio.

But what about spending about the same on a TCL 6 series? That Roku-powered TCL is my current Editors' Choice TV, but it's more than a year old and lacks quantum dots. In my comparisons the Vizio did show superior HDR color to the TCL, but the TCL won in other areas, in particular brightness. I'd still recommend the TCL to most buyers because of its superior smart TV system, but the Vizio is still an excellent choice. As long you make sure you're getting the right model of M-Series Quantum.

Normal-looking Vizio TV on the outside, quantum dots and local dimming in the inside

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Some 2019 M-Series TVs are worse than others

Unlike most TV makers, Vizio often includes TVs with significant variations in the same series. Unfortunately, the differences between models in 2019 M-Series Quantum are major enough that I had to exclude the majority of 2019 TVs in the series from this review.

There are two distinct sub-sets of 2019 M-Series Quantum TVs, one with a "7" in the model name (which I'll call M7s), and ones with an "8" (M8s). The M8 models cost more, have more local dimming zones and higher brightness. Otherwise the M7 and M8 have essentially the same features and specifications, including quantum dots. Here's how they break down.

There are two M8 models (65 and 55-inch) and four M7 models (65-, 55-, 50- and 43-inch). I reviewed a 65-inch M8 and am confident the 55-inch size will perform in a similar way, so it's included in this review.

I didn't review any of the four M7 models, however, so they are not included in this review. With significantly fewer local dimming zones and lower brightness, I don't think they'll perform as well as the M8 model I did review, so they won't get the same ratings. If I do review an M7 model I'll update this section.

To make it more confusing, many retailers including Wal-Mart, Target, Sam's Club and Costco carry both M7 and M8 models (as of June 2019 Amazon and Best Buy don't sell M7s, only M8s). Currently the M8 is about $100 more than the M7. Caveat emptor.

Minimalist design, sparse smarts

The cabinet of the M-Series Quantum is typically minimalist for today's TVs -- very little bezel around the screen, slightly thicker along the bottom -- but doesn't seem cheap. The corners are rounded on the top and the stand legs thin and matte black like the rest of the frame.

Vizio's remote has been unchanged for years and remains one of my least favorite. Yes, it gets the job done, but compared to the simplicity of Roku and Samsung remotes, or the evolved wands of LG and Sony, it's an also-ran.

The same goes for Vizio's smart TV system. The Quantum has the latest version, "Smartcast 3.0," which loads faster than before, but it's still sluggish compared to other systems, in particular Roku. With the Vizio next to a TCL 6 series Roku TV I moved through menus, launched apps and started streams from Netflix, Amazon and Hulu, and the Roku was much faster, in particular at loading its home page. Vizio has added a few apps and now allows me to rearrange apps on the bottom, but the main screen, filled with a random selection of TV shows and movies I didn't care about, is still worse than on any other current TV.

App selection lags behind other smart TVs, but the major names are all there. To watch any of the hundreds of apps not part of Vizio's on-screen system, you'll use the cast function on your phone to connect to the TV. The Vizio's Chromecast built-in feature is neat for phone-centric users, but less convenient for people used to on-screen apps. 

The ability to use your iPhone or iPad with Apple AirPlay on Vizio TVs is coming this summer, but I didn't get to test it for this review. Vizio doesn't have any voice capability built into its remote but the TV will work with Amazon Alexa and Google Home speakers.

More zones, cheaper dots

The biggest image quality improvements over last year's M-Series are more zones of full-array local dimming (FALD) and the addition of quantum dots. FALD is my favorite addition to for LCD picture quality because it improves all-important contrast and black levels. The number of dimmable zones is an important specification because it controls how precise the dimming can be. More zones doesn't necessarily mean better picture quality, but it usually helps. Both sizes in the M8 series have an impressive 90 zones, excellent for a TV at this price level.

Quantum dots, meanwhile, allow the M-Series to achieve better HDR color. The TV delivered a comparable color gamut to more-expensive QD-equipped TVs, such as Samsung's QLEDs, in my measurements.

The M-Series has a 60Hz refresh rate panel -- Vizio's claim of "120Hz effective" is fake news. It lacks a setting to engage MEMC (motion estimation, motion compensation), aka the Soap Opera Effect, as found on the more expensive Vizio P- and PX-Series, as well as TCL's 6 series. All of the sizes in the M-Series use VA panels, not the IPS panels found on some sizes in previous years. Vizio supports both major types of HDR, HDR10 and Dolby Vision, in the M-Series. So does every other major TV maker except Samsung, which lacks Dolby Vision support.

• 4 HDMI inputs (All version 2.0)
• 1 analog composite video input
• 1 USB port
• RF antenna tuner input
• Ethernet port
• Optical digital audio output
• Stereo analog audio output

Unlike some 2019 TV makers Vizio isn't supporting any HDMI 2.1 features like auto game mode and variable refresh rate, but most buyers won't miss them. Otherwise the selection of connections matches competitors.

Picture quality

The M-Series Quantum belted out excellent picture quality overall, largely thanks to the performance of its full-array local dimming. In dark scenes black levels were as good or better, depending on content, than the more-expensive Samsung and Sony TVs in my comparison, and about the same or slightly worse than the TCL and Vizio PQ. The other TVs got brighter in HDR than the Vizio however, although the TCL's color wasn't as good.

Click the image at the right to see the picture settings used in the review and to read more about how this TV's picture controls worked during calibration.

Dim lighting: The M-Series Quantum performed very well in two of my favorite dark test scenes, The Long Night from Game of Thrones' final season and the attack on Hogwarts from Chapter 12 of Harry Potter and the Deathly Hallows, Part 2. In both cases it delivered black levels as deep or deeper than any of the other LCD TVs, in combination with superb shadow detail and minimal blooming. I could point to some differences here and there, but they'd be nitpicks, and of course the OLED looked better than any of the LCDs.

Bright lighting: The M-Series Quantum isn't a dim TV, but its measurements reveal lower light output than many competitors. On the other hand it matches Vizio's 600 nits specification almost exactly with both HDR and SDR content in its brightest picture modes (Vivid).

The table above shows the 2019 M-Series Quantum versus a handful of comparable sets, and it's worth noting that the 2018 M-Series and TCL 6 series got quite a bit brighter in my tests. Vizio's Calibrated picture mode delivered the most-accurate picture, which is well worth the loss of nits compared to Vivid.

The M's semimatte screen finish reduced reflections as well as any TV in my lineup, with the exception of the Samsung and the LG OLED, and beat the TCL in this area. It preserved black levels about as well as the Sony and TCL, but worse than the others.

Color accuracy: The highly accurate color of the M-Series Quantum showed up in test patterns and program material. Measurements both before and after calibration were as good as I'd expect from any TV. Watching HBO's Big Little Lies, the skin tones of the actors and the bright colors of the elementary school as they drop their kids off looked pleasingly realistic.
Video processing: The Vizio M-Series Quantum was essentially the same as the 2018 version in this area. It behaved like a 60Hz TV in my motion tests, meaning it didn't reduce blur as well as higher-end sets with a 120Hz refresh rate. I'm not particularly sensitive to motion blur, but if you are, a true 120Hz TV like Vizio's step-up P-Series Quantum might be worth the extra money.

The M registered proper 1080p/24 cadence but exhibited motion resolution of just 300 lines. Vizio does offer a Clear Action control that improves that number to a respectable 900 (as long as the Active Full Array backlight control is at Low or Off), but as usual it introduced flicker and dimmed the image, so most viewers will want to avoid it. Unlike some 60Hz TVs such as the TCL 6 series, there's no option to engage smoothing, aka the Soap Opera Effect.

With 1080p/HD sources input lag for gaming was excellent, with a result of 21ms whether or not I used the Gaming Low Latency setting. With 4K HDR sources that setting made a huge difference. I measured a lackluster 66ms with GLL turned off, and a superb 20.5ms with it engaged. Those results are a bit short of the TCL but still very respectable.

Uniformity: The M-Series Quantum had no major issues in this category, with a relatively uniform image across the screen and little or no variation at different light levels with full-field test patterns. If maintained color and contrast from off-angle -- seats to either side of the sweet spot in front of the screen -- as well as any of the others, and better than the Sony.

Best 4K Blu-rays

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HDR and 4K video: Overall the M-Series looked very good with HDR, especially for the price, with plenty of juicy contrast and impressive impact. In certain areas it outperformed some of the TVs in my lineup (with the exception of the LG OLED) but fell short in other areas. For this round of 4K HDR testing I compared all six sets side-by-side in the default settings of their best picture modes. My source was the incredible-looking montage of images from the new 4K HDR benchmark disc from Spears and Munsil.

The first difference I noticed was the M-Series was dimmer than any of the sets overall, in terms of both specular highlights and full-screen brightness and impact in many scenes. One of the most prominent specular instances is the sun shining through a satellite dish (5:30), and spot measurements put it at more than 100 nits dimmer on the M-Series (145) than on any of the other sets, including the TCL (the next-dimmest at 266). That difference was easy to see with the naked eye in my side-by-side comparison.

Local dimming performance on the Vizio was excellent, however, which in many scenes led to excellent contrast despite its relative dimness. In the challenging section where objects appear before a black background (2:43), the M-Series maintained a darker shade of black and less blooming than any of the other LCDs aside from the P-Series Quantum and the TCL. Meanwhile black levels and blooming on the Samsung and especially the Sony were both quite a bit brighter than either one, and of course the OLED looked the best.

Watching the nighttime cityscapes (4:21), the M delivered slightly better contrast and darker shadows among the buildings than the Samsung and Sony, but its slightly dimmer highlights resulted in similar overall contrast between the three, with no clear advantage.

Colors in HDR, for example the flowers and insects in Chapter 7, looked great on all of the TVs, with vibrant reds and oranges in particular. The exception was the TCL, which pushed all of the colors too much, resulting in a too-garish rendition of these natural objects when compared to the other displays.

I did notice a tiny bit of color banding on the M-Series, for example in the sunset sky over a lake (2:03) and in daylit skies over another lake (4:58) and a satellite array (5:30), where the colors blended together better on the Sony, Samsung and LG. The TCL was about the same as the M-Series in these shots while banding on the P-Series Quantum was quite a bit worse.

Test discs are fun but for a more real-world video comparison I checked out Hanna on Amazon Prime Video streamed from a Roku Ultra. The show has a lot of nice HDR effects and the scenes I compared from the beginning of Episode 8 revealed pretty much all of the same differences I noted in the test disc above. Again highlights (like the sun through a doorway at 2:08) and the image overall was somewhat dimmer on the M-Series Quantum, but thanks to solid black levels and local dimming the image still had lots of impact, and colors looked great.