I hate to say it because I love all things Disney, but Stitch disappoints me. I think it may have to do with it being released around the same time as a lot of other new rides and attractions.
I went to Disney in Dec 03 and didn't make it back to July 05. By this time, Soarin', CinderellaBration, Lights Motors Action and Turtle Talk with Crush were also new to me. They all blew me away and then I tried Stitch and I just didn't get it. It's supposed to be a pre-Lilo and Stitch story but it doesn't work with storyline of the movie. Secondly, the best part of the attraction to me is the second chamber with the Sargent.
The attraction itself is simply a series of sensory tricks that are cool the first time but predicatable every time after. What I mean is I can ride Big Thunder 20 times or Splash Mtn and see something new everytime. I can do Stitch (which I've done three or four times) and I already know what's going to happen before it does. It's too predicatable and built too much on having a cool AA. I don't think Stitch is gonna last too much longer without a revamp. The last couple times I've been there, including this past weekend, the lines are small and I don't think that bodes well with this being so new.
Anyways, I'd say ride it once because the first time everything will catch you by surprise. After that I think you'll want to skip it unless everythings a long wait and it has no line.