I have bought Enigmo, Crash Bandicoot Racing, and Money ball. Racing and Monkey ball are definitely fun, but in my opinion not in the same league as Enigmo. It is the type of game where you can sit back and try to figure out the puzzle. Not a lot of movement to make you look like a crazy person, but it keeps you thinking and is a perfect time killer.
I would recommend Super Monkey Ball 100x more than I would recommend Crash. The graphics are better, the frame rate is amazingly better, and the controls are just as good. Crash was a big disappointment for me.