I read many of the reviews before purchasing this item.  Many wrote it was week on the upper sections.  I played carpeneter; I glued and added a few screws to each piece as I put it together.  It is very strong and will last for years.   The cat likes, I like it, but the birds on outside are worried. The cat seens a bit closer. It looks good. It is nicely priced.

Pros: It has all the tools a cat likes.  Places to hide, roped scratching posts, many levels to jump on,  and soft enough to sleep on. 
Cons: It is a bit week/wobbly at the top but with good glue and few screws, Its a gem.