I have a 360 now, but I almost never use it. I much prefer the Wii for the controls (not fond of dual analog) and the games. I play to unwind and am very often doing more than one thing simultaneously. With Wii there's lots of games you can play one handed (esp adventure). Also lots of games to play in quick bursts. Often I won't get back to a game for months, and I won't have time to refigure out controls so if it's not pick-up and play it's useless to me.
And then there's the party aspects, there's simply more on Wii I can play with friends, especially girlfriends. Plus fitness. And faaaarrrr too many games on Wii I want, and already own, than I even have time to play.
I had hoped to play Mass Effect and Dragon's Age on 360 but I simply haven't the time for those. Nothing else on the system interests me.