Not comfortable for grown cats
Whoever designed this doesn't know cats.
It is not all that hefty, I can slide it around the room with only a little effort. The various platforms are not adequately sized for my fairly small cat to relax and lie fully, sleeping, or immersed in bird watching. She can sit up straight on them. And lie tightly curled on the top level or in the den. Because it lacks heft it wobbles a lot when she moves about on it. Scratch posts are positioned awkwardly, she can't fully stretch and scratch.