I think the biggest push for me is that the JVC will not only have better black levels, but the loss in contrast reported from a number of Sony LCoS owners in recent years makes me worry about the long term quality which Sony offers. That's my biggest push towards JVC.
As far as screens go...
I think there are probably a number of similar screens out there, but the main goal of any screen is the most accurate reflection of video content back into the room. Most screens have some texture to them. This is required so that when light hits the screen it doesn't just 'reflect' like a mirror. But it is diffused and scatters in all directions evenly. The smoother the screen, the more reflective it will be, and this creates hot-spots. Think of a dry-erase white board vs. your painted wall. While the dry erase board is more reflective, it's not diffuse enough and you get a poor image on it. But, the wall will show texture. That texture will impact image quality.
So, the HD Progressive materials from DaLite are incredibly smooth. You can't really see any texture to those materials at all. Yet, they are also VERY diffuse. So, you get an extremely wide viewing angle with a very smooth image both left to right and top to bottom, with a very neutral, color balanced, screen surface.
This screen material used to be marketed as JKP Affinity screens by DaLite and were designed by Joe Kane Productions (I believe) and were introduced as their high-end home-theater screen. Of which, I am in agreement with.
The cost is similar to what a ALR screen may run, so about $1,500 more than their DaMat material (standard white matte finish). Since a screen could easily be a 20-year purchase, or more, if well taken care of, I think that the extra money spent is worth it for the long term in a really nice home theater space where budget allows it.
If I could NOT afford it, then the DaMat is similar to about 100 other standard flat screens on the market and I would probably just get a Silver Ticket screen. For that matter, if I wanted to save some money for the first few years and maybe get a better screen later, I would get a Silver Ticket white screen from Amazon and call it a day. They are surprisingly good quality for the money and really are similar to what mid-tier manufacturers offer for $1,000 more.