We bought this for a stray cat that we brought into to our house, as her "safe" place, that sorta worked. All 4 cats fell in love with it and they all sleep in/on it lol. Needless to say the stray fit right in.
It was pretty easy to put together, just look at the picture on the box if the directions aren't helping, as they are basic. Its fairly sturdy, although when my 17lb cat jumps on the top platform its a bit shaky, but it won't fall over. It certainly holds all 4 cats on it at one time. The toys were ripped off in the 1st 10 seconds (our cats are little heathens lol) but they make for good batting around the house toys. All in all we are very happy with this purchase and I'd recommend it, especially as you can't beat the price compared to other stores for something thats not nearly as nice.