This is the best cat tree!  It is super sturdy-my kids are fast little beasties and they jump and climb on this thing constantly.  I put it by a window so they can see out and feel "up high" and they love it.  They are on it when I come home for lunch every day.  I left the house-part off it so there is a large platform for them both to hang out. For us, it works better than way and they love the little house!  I put it on the floor and they are always playing in and around it.  
It was pretty easy to put together with another person.  Very study and I was impressed that the posts were wrapped in twine.  It didn't say that in the ad.  Great item for a GREAT price.  I'll buy from these guys again!  
My family says THANK YOU!!