It probably took around 2 hours to put together and the instructions are pretty bad but it wasn't too hard to figure out from the picture.  The only negatives about the tree itself is that the hammoks need longer screws to keep them in, they keep falling out even with the posts they rest on securely attached.  Also the tall platform on the left and the shorter platform on the right only attach with one big screw through the bottom so they're a bit wobbly when the cats are jumping to and from them, but so far they've held up.  The cats seem to enjoy it :)