I've had cat trees before but this one is the best! Easy to assemble. (the allen key was actually big enough to hold on to). I was concerned about screwing on the posts but this thing is so well made it isn't an issue. I am impressed with how sturdy it is. I have four cats and the two biggest ones play chase. They put quit a stress load when they hit the tree running but the tree is holding up well.  

Pros: easy assembly, well made, good materials