Depends. Do you really want to learn how to use it in its fullest extent, or are you going to use it just a handful of times then forget about it?
For us avid builders, it's worth the $30 we paid a long time ago. I've been using for I forgot how long, and I still use it every day.
As far as problems go, yeah there are some. The spinner program isn't all that great. There are only 2 speeds in the editor: fast and faster. For small rides, that's blisteringly fast and supersonic.
Otherwise, no, no problems.