I would have like to give this a 5 star review but I feel the top 2 platforms should be larger.  Many cats are: 
a.) larger than the platforms
b.) like to stretch out a bit at times.
They took to it immediately and use it at all times, day and night.  Especially used are the scratching posts, and platforms at the 2 top levels.  
I like it especially b/c it is easy to  clean and it keeps them off the furniture.  Well, not always, but enough to keep the furniture clean longer!
It was definitely easy to put together and I'm over 70 and have arthritis.  However, I would recommend, as I would for any assembly, that you read the directions carefully to get it together quickly.
Would definitely buy it again, and have recommended it to others.