I'm glad they're using AAs rather than rechargeable batteries tbh. That way, I can use my decent Duracell rechargeables. The play and charge kit was one of the worst accessories I've ever experienced - the battery wouldn't last more than a year without dying. Which is fine for a £10 battery (which I luckily always managed to get exchanged under warranty), but not for a £50 controller. I went through 4 of them before giving up and just using rechargeable AAs.
My original (Phat) PS3 controller still seems to hold a charge fairly decently. Not sure why MS can't manage the same with their batteries.