Peaceful yet chaotic, adorable yet horrifying. There's not a lot to do in Multiwinia, but it's incredibly satisfying and fun to watch anyway. I've seen many a fight morph the from the standard (typical distrubutions of forces advancing and retreating) to the bat♥♥♥♥ insane (alien invaders and giant monsters eat everything while dark forests grow claiming the souls of many; blood rains in the sky as nukes and airstrikes are called in all over the war-torn map).
You'll see what I mean. Make sure to play on mulitiplayer (preferably with skype), the experience is wonderful.
Is it worth ten dollars? Probably not, so wait for a sale. That said, if all of your friends already have it and you've got money buring a hole in your pocket, Multiwinia isn't a bad choice at all.