I purchased one of these about two years ago for my new kitten... And he loved it. It let him get high up and have a great lay of the land. Plenty of places to scratch and sharpen his claws.
I moved cross-country and couldn't bring much more than a few suitcases worth of stuff, needless to say I had to leave the Armakat cat-tree behind. My cat misses it, and my new tweed furniture feels the loss even more.
It is tall, and sways a little, but placing it in a corner or against a wall seems to solve most of these problems, not that the cat ever seemed to mind. You will occasionally need to tighten the bolts holding it together, and the little fuzzy dingle-balls lasted literally SECONDS before my cat tore them off - but all in all your cat will have a lot of fun on this cat-tree.