Previous ratings I had read indicated it was functional for cats up to 25 pounds.  Our 2 cats are under that, and the one lounge area is too small and the top is so small they don't feel comfortable laying on it.  While putting it together, I discovered I was missing the 2 bolts that were needed to attach the ladder (a comment I had read about this piece indicated that the holes weren't in the right place anyway).  Needless to say, the ladder isn't on the tree, and if it was the cats wouldn't use it to get to the next level because of the size of the hole for the cat to go through.  It is built to sit in a corner, and that is where it will sit in order to maintain stability.