WE have one cat and 2 small dogs...they ALL love it.  The cat plays with the toys constantly and the dogs are always in and out of it.  The cat has claimed the top perch, tho.  It looks 10x better in person than the pic, too.  This was a great purchase!

Pros: Super easy to assemble!  It basically just pops up and you put the top on.  Very cool!
Cons: none