The new Vizio M-Series for 2015 is a good budget 4k TV, and in some cases, even better than the P Series. As long as you don't expect a perfect TV, it is a good purchase.
For the price, the new M Series for 2015 is a really good 4k TV. It upscales 1080p better than the P Series, however, its local dimming is not as good. The two main downsides to this TV are the long motion blur trail and the loss of saturation at an angle.
The 2015 Vizio M looks higher-end than last year's did. It even feels slightly more premium than the P Series.
This TV has a very wide stand with cast metal feet. It is very sturdy, but you will need a table as wide as the TV itself.
This TV's contrast ratio is great. The local dimming feature did have an effect on the black level of our checkboard pattern, but it also affected the white boxes, which isn't good.
As with the E series, the local dimming dims the highlights. It darkens brighter objects on the screen considerably when they are alone on a dark background. In our test video, you can see that the white dot is darker than it should be. Of course, there is less blooming that way, but it's not good to have the object appear too dark. The P Series handled our test pattern better, and it has more zones, too.
With solid colors, you can see some dirty screen effect caused by the full array backlight. There's also a pretty significant amount of deviation to the uniformity.
This TV loses saturation when you are off-axis.
Update 01/06/2017: We have changed the methodology of testing. Since this is an old TV which we don't have anymore, we extrapolated the results from 2016 TVs.
The black uniformity was great, even when local dimming was turned off.
The white balance calibration is really good by default under the 'Calibrated' picture mode. However, the colors are a bit off.
The red and blue colors couldn't be completely fixed, but the rest is great.
We had to increase sharpness to 25 for our 480p test, as otherwise it was really blurry. See here for more details. The P Series didn't have that issue. The noise reduction features work, but they are not very effective. Also, setting 'Reduce Block Noise' to 'High' resulted in a drastic loss of sharpness, so we used Medium instead.
Sharpness also had to be increase to 25 for 720p content to make it looks less blurry.
Upscaled 1080p content looks a lot better than on the P Series, under the exact same settings.
It reflects an average amount of light.
It can get bright enough that it should be able to handle almost any room.
Unfortunately, like the P Series, this TV has a very long trail following moving objects. In our picture, you can see that the brighter trail even continues outside the picture. This shouldn't be an issue with normal content, but it could be a problem for video games.
The input lag is really low when using the HDMI 5 input and turning on 'Game Low Latency'.
It doesn't support chroma 4:4:4 unfortunately at any resolution/refresh rate. This doesn't matter for movies or even video games, you will only see a difference for a PC monitor. 4:2:2 works though.
1080p @ 120fps works (although only for the 60" model and up), which is great for gaming on a PC.
HDMI port 5 behaves differently from the others. See our Additional Review Notes
Relatively good frequency response and loudness. However, at higher volumes, the frequency response gets worse and pumping artifacts may be present. The bass extension is not the best.
Low distortion at lower volumes, but the distortion becomes significant when the TV is pushed hard.
Vizio's app selection is limited, as is its codec support. There is no web browser.
The back of the remote is a QWERTY keyboard, which is handy for inputting text. A smart remote like you get with higher-end LG and Samsung TVs would be better, though.