I have one. It's really quite boring. It just burrows under the sand and sleeps for a week or two, then comes out for an hour and then back under the sand.
I had a hard time feeding it. It didn't really eat anything. I can only guess that it eats 'pods in the sand.
If you keep one, make sure you have at least 3" of soft sand (gravel won't work) for him to bury under.
-Nathan
PS Yes they are kind of clumsy, but I never had it "knock" my decorations around. It just sort of bumps into them.