Got the projector up and going last night, one word - WOW! I've had my LG PA70G installed in my room for a while, so the projector experience is not new to me, nor is experiencing a nice projector, but the HC7900DW really exceeded my expectations and then some.
I booted up into my XBMC welcome screen and it was something I've seen a million times before, but it blew me away how sharp and clear it was. I sat back and watched some of Avatar in 1080P and it was clearer and more detailed than I can ever remember, even in the theater when it came out.
Setup was super easy compared to getting my PA70G with no zoom (not to mention no lens shift) setup. I think the lens ended up being about 150" away from the screen, but otherwise it'd be right underneath/very close to the light fixture which is right there, so I think I choose the right place to install it based on my room. I must have messed with my PA70G for 4-5 hours getting it setup right (lots of measuring and tweaking with my Monoprice mount), so I was a little shocked when I put it the HC7900DW up there and had it projecting an amazingly sharp and crisp picture in about 3 minutes after getting the top bracket secured to a set of 2x8's I put up in my attic.
Running in low lamp mode on a new lamp, 110" 1.2 gain screen the image is plenty bright enough for me in 2D. Even if it loses 30% of the lumens I still see low lamp being fine except during sports with some ambient light. I was pretty worried about the image brightness, but I've really got no complaints. The black levels are in a whole different league from the PA70G and then some, even with mild settings on the iris. CFI is cool to play with, and at low settings I think it brings out a lot of motion detail in movies without making it seem like a soap opera.
This thing is an absolute bargain for its current price. Totally pleased with my purchase. Now I get to do the RF 3D hack and experience some of that.