What a difference 2 weeks makes
Since it now appears highly unlikely that the Vizio Reference Series is going to make it out this year (and is much more likely to materialize as a new product line in 2015), the M and the P look like they will be the only products to emerge in 2014 (in addition to the E-Series which is largely already out).
So I've come to the conclusion that if I want to get a new TV this year as a 'placeholder' for another year or two while we see what happens with OLED and as the standards for HDR and 4K content stabilize and hopefully materialize, it's going to be one of these two TVs from Vizio. It's also more solidly rumored now that the M Series will emerge in May and the P Series in August.
I'm not particularly motivated by 4K at this stage, so local dimming performance (and specifically good dark-level and shadow detail without distracting blooming) will be the most important factor in determining whether the M is a keeper for me or I want to wait for the P. Also, having dug into the specs a bit deeper, I have a better understanding of the ways in which the P is likely to vary from the M. Here's a recap of my current understanding/expectation:
Release Date___________May 2014_____August 2014
Resolution______________1080p _______4K (UHDTV)
Clear Action Rate________720Hz________960Hz
Backlight Brightness____350-450 Nits____400_600 Nits
Effective Refresh Rate__160-360Hz______240-480Hz
Local Dimming Zones_____32 (8Vx4H)____64 (8Vx8H)
24fps Cinema Mode______yes?__________yes
48fps Cinema Mode______yes?__________yes
Active Pixel Tuning_______yes___________yes
High Velocity Mode_______no?___________yes
As already stated, the larger number of dimming zones in the P Series should allow for some improvement in blacks/shadow detail/lack of blooming, but 32 and 64 are both a small number of local dimming zones (compared tot he Sharp Elite with over 200 ldzs or the Vizio Reference Series with 384 ldzs), so it is unclear how different the performance of these two panels will be. Said another way, if Vizio has discovered some new 'secret sauce' (such as Active Pixel Tuning, for example) to greatly improve local dimming performance with only 64 ldzs, there is a good chance that much of that same improvement would also be visible with half the number of ldzs...
Letterbox bars for widescreen movies should be completely blacked out on both the M and the P, but when viewing 4:3 content, the P should deliver completely black letterbox bars while the M will not be able to (not a big deal to me, bit an advantage of 8V x 8H dimming zones versus 8V x 4H dimming zones.
We don't yet know what the brightness of the backlights in these to lines will be, which will end up determining how the 'Clear Action Rate' translates into actual motion blur reduction. It is very unlikely that the M Series will reduce the current backlight brightness of 350 Nits on 2013 products and between the 'factor of 3' that they have hinted at through the Clear Action Rate spec of 720Hz, I believe they may increase the backscreen brightness of the 2014 M Series to 33% more than the 2014 E-Series, which would mean 450 Nits, so that is how I arrived at a range of 350-450 Nits for the M. For the P Series, I doubt it will have a less bright Backlight than the 2013 M-Series and the Clear Action Rate of 960Hz they have hinted at implies they may increase backlight brightness of the P Series to double the brightness of the E-Series, hence the 350-600 Nit range I arrived at. (Also, since the R Series has 800 Nits and the E Series has 300 Nits, a progression of E@300, M@450, P@600, R@800 Nits makes sense from a lineup progression point of view.
The brightness of the backlight only really impacts the Effective Refresh Rate these TVs actually deliver (which is almost certainly lower than the Clear Action Rate they specify as the image would be too dim at those true action rates. I've put the range of Effective Refresh Rates that correspond to the backlight brightness range I have assumed. In any case, both of these panels should perform at least as well as the 2013M Series in terms of Effective Refresh Rate and motion blur reduction (and will hopefully perform better, with the P hopefully delivering twice the performance of the 2013 M Series if it does get the 600 Nit backlight I am hoping for).
The P Series supports a native 24fps/48fps 'Pure Cinema Mode' and with a 120Hz native panel and a scanning backlight, the M Series could support this same 24fps/48fps true Cinema Mode, but it is unclear if the M will offer this feature or if it has been held back for a 'dumbing down' marketing strategy. The 2013 M Series supported a 'Film Mode' so hopefully this was a true 24fps/48fps Cinema Mode and it will continue to be supported...
The P Series explicitly lists a 120Hz 'High Velocity Mode' for gaming which should also be a feature that can be supported by the M Series panel, but since no mention is made of it, it may have been held back for a 'dumbing down' marketing strategy.
The contrast of the P Series is supposedly 50 million to 1 versus the M with 'only' 20 million to 1, so it would appear that they are doing something different between the two panels to 'dumb down' this spec for the M Series. Perhaps the 'off' ldzs of the M Series are not brought down as nearly of an 'OFF' state as the P Series... In any case, it is difficult to understand what this will end up meaning until the black leve/shadow detail/lack of blooming of the two panels can be assessed. In the case that the backlight brightness is affecting this spec, it may indicate that the backlight of the P Series is as much as 250% the brightness of the (though it would surprise me if the P were that much brighter than the M, since even if the M were only 300 Nits like the E, that would put the P at 750Nits very close to the R Series at 800 Nits...).
Knowing that the R Series is unlikely to materialize this year and that the P will not be out until August, I'm starting to lean towards picking up an M Series in May. If it has noticeable blooming I can return in and try a P Series 4 months later in the hope that the additional dimming zones makes any blooming more palatable, and if the M with only 32 zones does a good-enough job delivering blacks and shadow detail without too much blooming, I can live with that for a year or two while HDR technology and low-cost Elite-like FALD LED/LCDs continue to mature...