I've had the cat condo a little over a week now, and it's working pretty well, so far. Newton likes to lounge on the perch - all the scratching posts and the little hanging ball get a lot of use. The little 'rooms' themselves aren't used as much, but they do dart in and out of them sometimes during playtime.
The structure rocks a bit when the cats are jumping on or off, but it stays in place. I'm pretty happy with it (especially for the price).
And now that I've added cat walkways in this room as well, it should make for a pretty fun place to hang out