Well, just like so many reviews I read before purchasing this item, my kitty would hardly let me put it together!  He was jumping all over it and would try to swat my hand while I was tightening the bolts for the next level.  I had to keep stopping until he calmed down...  It is fantastic entertainment for sure!  For all of us!  No problems putting it together - very simple!  It is extremely sturdy to hold up under the vigorous activity my kitty puts it through!  He also sleeps on it a lot!  We put his bed on the level just below the apartment.  Also, it is accomplishing the purpose intended to a great degree, which was diverting him from using our furniture as his playground.  I am very, very happy with it and have no hesitation in recommending it to others.