rumble sucks up battery life like crazy.. it's actually quite impressive that the 360 controllers get the life they do.
Bluetooth sucks up a lot of battery life too (a bit more then some other protocols IIRC). I think Nintendo gets around that by using a single less powerful motor and lighter weight (the remote has more of a buzz then a rumble)... though even using a headset on my 360 controller my Wii remotes kills batteries twice as fast as the 360 does... I'm guessing due to bluetooth.
At least the sixaxis has the benefit of no speaker or headset to drive from the controller... still it will be interesting to see how much battery life they can get out of them.
I'm hoping the new controller will at least have a user serviceable battery, especially if you're going to have to charge it more often, shortening it's lifespan. ideally I'd like to see it use AAs (so I can use the same rechargeables that I use for the 360 and Wii) but that doesn't seem to be sony's style... I don't know of any wireless sony device that doesn't use a proprietary battery