I have three different brands of cat trees. Molly and Friends makes the BEST and sturdiest trees, however, they are VERY expensive. I chose a 36" one for Raiden. I also have one from North American that is a piece of crap. It tipped over every time Raiden hopped on or off so had to put a larger square of plywood under the base so it didn't. The Armakat tree is Raiden's favorite. It was the cheapest of all the trees. Very well made and they have many to choose from. I needed a smaller footprint as I have shorter windowless walls. Amazon in the UK will have a great selection at great prices. The space you have available will determine the size of tree you can get. Know that the kitties are not usually particular.