Easy to put together, no extra tools needed besides the included one, an excellent price, (was double this price at my local pet store),  and my two cats like the different levels to lay on. It's very stable and doesn't wobble...even when my 20-pounder  jumps up and down on it. The perches on top are a slight bit small for him but he still gets up there and curls up on them. He fits nicely into the box part and spends the afternoons snoozing in there.