Interesting
Interesting idea, but not a real winner in the end. What was interesting to observe, though, was how my opinion changed over time - I went from "what's this?" to "hey, this is neat" very quickly, but - ultimately - also continued to "meh, this is getting kinda boring" comparativel quickly, too.
Put more succinctly: it's fun for a while, but it doesn't hold your interest for that long (well, mine, anyway), and it doesn't have much replay value.
Of course, YMMV.