So for, so good with this cat tree.  I have only had it up for a few weeks.  The top beds only screw in about 1/2 way, but they seem stable.  I am not sure if this is on purpose or not, but they do not wobble, so I am not overly concerned about it.  It is taking my cats a little time to get used to this one, but they are using it.

Pros: Easy to assemble, lots of room for cats
Cons: Top beds only screw in 1/2 way