We bought two of these at a great price hoping they were as good as many reviews stated.  I opened them up and just made the sides into a square then put the bed in the bottom, all of a sudden it was very sturdy.  Put the top bed on and put a little catnip on both beds.  I did the same with the other one.   We have four rescue cats and most evenings there is one cat sleeping on the bottom bed and one on the top on both cat condos.  They all love them, great product.

Pros: great value, great product, very sturdy
Cons: none