I am using a High Contrast Matte White Dalite screen with my PLV70, and I think the blacks and contrasts are great. Of course, I don't really know any better, either.

It is an in-ceiling installation (Advantage Manual in DaLite parlance).
My problem is that I see horizontal bands on the image in light scenes. Photo examples
here . I called the folks I bought my PJ from and also Sanyo about it.
Well, last night (right after I put calls into Sanyo and Presenting Solutions) I figured out what it is...... They are ripples on the screen itself! They move with the screen, not the PJ (if I do lens shift or move the PJ). Duhhhh :b
I'm going to have to look at other screen options, I guess. I really like the performance of the HCMW screen! The blacks are great - check out the blacks on the top image at the link above! It is a very bright image and the black letterboxing above and below (LOR is wider than wide) is virtually indistinguishable from the screen's matte black surrounds. Who says LCD has poor blacks?
I also like the matte screen because there are NO viewing angle constraints. The picture looks the same from any angle, even acute angles from those sitting on the couch along the left wall.
Finally, I believe a low-gain (<1) screen is best for me since the PLV-70 is such a light cannon (2200 base lumens), that I don't need any gain. We have a very watchable image in daylight and with all the lights on full in the room. Gets REALLY good in the dark.

The higher the screen gain, the more ambient light would show up as poor or off-color blacks, I think. I wonder sometimes how this may have been a factor for those who report bad or off-color blacks with a PJ?? I can imagine if a HT had, say, green wall sconces on, the blacks would take a greenish hue.
As a newbie to HT, I'm just guessing at most of this, but if any of you have any screen advice, please chime in! Those ripples are driving me nuts!
Oh- using a wall or fixed screen is not an option, which is evident in my HT pictures posted per the link in my sig.
Thanks,
Gordon