you owe an RS20 and all its capabilities. Last year two american sites, the most known ones ( though one of them has too much of subjective view, which is important, but lacks in technical aspects), were unanimous in consider the RS 20 the champion.
Of course there's DLP and LCD fans. I havent' seen the perfomrnance of the first. Some units are quite expensive, but, according to specialized press, they don't provide black level as the LCOS/SXRD do and some LCD achieve. I went on Sony while it were in LCD projectors line and on Mitsubishi. I had the HC 5000 and the HC 7000, and both were much plagued by the dust blobs issue. They hit my units just a bit above 100 hours of use. The image of the HC7000 was extremely good to me, but I wouldn't stand the blobs, as much as one doesn't support rainbow effects. I think it's something inherent to LCD. I sold it out and bought the RS 10 ( in black scenes it just eats up the hC 7000). My projection room is not a bat cave but completley light controlled. Pretty much dark. I decided to take a step forward, which is the RS 25. The RS 20 would be an upgrade itself.
Reading your post (with all your cautioness), made me think (I know nothing about technical aspects) that front projectors have reached a level of perfornance, IMHO, hard to improve. I mean JVC, RS 25 and, this year, Sony's VW 85, wil be the top ones. Differences, I believe, will be too short, if they come to exist.
One thing, however, caught my attention very positively, at least by now. The RS 25 owners are reporting a very sharp image, what I enjoyed too much in the LCD units.
The basic point in JVC, appreciated by too many people, is its CRT-like image. I noticed, in this point, with a certain degree of deception, that the HC 7000 showed a more dynamic image than the RS 10, though, as I said, the blacks in the last one were noticeably better. The not use of a DI, also, has a great advantage, not keepin the bright objects dim in dark scenes.
In Brazil we don't have ISF calibrators. Personally, I prefer the image a little saturated (not as much to spoil the image). The settings I get from sites that provided and members that post them. I'm certain I'm not getting the best of my RS 10, but so far, I'm really really happy with it.
In summary, my friend, If the RS25 comes to be an RS 20 sharper, I'll be fully satisfied.