This is a great cat condo and our two cats are on it all the time.  It is pretty solid, with a heavy base so it does not move much when being climbed upon by both cats at the same time (one weighs 15 lbs, the other 12 lbs).  It is also easy to put together.  My reason for 4 stars rather than 5 is because one of the upright posts would not screw into the base because the nut it was supposed to go into was way out of alignment.  In the end, we had to drill away part of the base platform in order for the screw in the upright and the base to align so that one would fit into the other.  That would be my only criticism about this unit.  All other parts fitted together perfectly.  Lastly, it arrived pretty much on time and in good condition (ie, undamaged).  I am pleased with this purchase.