I have a Stewart microperf screen, largely because my ceiling height is abnormally low--6' 7" floor-to-ceiling. The room, obviously, was not designed as a projection room http://www.avsforum.com/ubb/wink.gif
With my 92" diagonal screen size (16:9), the bottom of the screen is just 20" from the floor, and there is NO space above. I can adjust it a little in either direction, but not really enough to get the center channel up to a decent level. So I'm pretty much stuck with a microperf screen in this house.
I can't say I'm happy about that - I am 13+ feet from the screen, and I can still EASILY see the perforations. It's especially bad in my case, because my projector is an LCD model and the screen dooring is visible if I get much closer to the screen than 12'.
When it got installed, I was -stunned- at how much light went through to the wall behind! It's a regular picture back there! I definitely advise going with a pretty high-gain screen unless you are in a really controlled environment. Mine's a 1.7 gain model and is just barely sufficient with my 1000 lumens projector and a partially controlled light environment.
I'd advise more than one careful screening before choosing to go with a microperf screen, based on my experience. I looked at this very model of screen, and I htink that the one in my installation is much more noticable than the one at the store. I think part of that is the projector (theirs is on an 8" CRT) and part of it is just the environment.
As far as the audio, though, I can't say that I'm disappointed. Mine came with a small device that is placed in the audio chain for the center channel. It compensates for the rolloff of the high treble through the screen. I am pretty picky about my L-R speakers for music, but I'm not so picky about center for movies, and to my ears (which are often distracted watching movies), the audio response is just fine, even through the screen.
I guess I could dig out the old Stereophile test CDs to measure the response difference if someone's that interested...