After some research, we settled on this cat tree because it seemed quite stable compared to others. After a few days of test driving, I have to say that it is indeed quite stable and very beautiful. It has relatively easy assembly, just requires a little attention at some steps to be done correctly and to avoid unscrewing and rescrewing! My kitty is 6 kg, fits comfortably in the little house and particularly enjoys it. I believe it can easily withstand a second cat. I give it 4 stars because I would like a slightly better quality in the fabric. It doesn't shed, but it's questionable how well it will hold up against cat play. Other than that, it is a decent cat tree. It is quite stable even at the top level as it is supported by two legs, while the other levels are supported by four. I will return if anything changes in the future!

Super easy to assemble, and very beautiful. The little cats sit there almost all day, from the very first moment. One of them is constantly scratching it with her claws, the other not so much yet. They have really honored the nest-house and the top piece.
It is relatively sturdy and has wall support if needed. I have left it like this, and although it doesn't lean well against the wall, and even though the cats jump up and down with force and the tree shakes, it hasn't moved from its place.
I recommend it 100%.

Quality is fine and relatively easy to set up, spacious little house, I might have the most fearful cat because she didn't even honor it, she probably needs to get used to its presence first and maybe she will warm up to it now, time will tell.