I stopped using mine yesterday. So far, my battery life seems a bit better. I think most people get a new android, start playing with it way more than one would after having one for a bit.
Within the first couple hours, realize their battery is dead. So then they start looking into why, and they quickly find a task killer. They start using it non stop. Battery life starts to improve, great, problem solved.
People seem to forget that the first few days or more, they are installing and customizing heavily. They got a false impression from the task killer. Its not saving battery, they are usually not using the phone as much.
I still have my task killer installed, just not running. Ill only use it if i get a crappy app or am having a problem with an app and it needs to be closed via a task manager.
I still have my iPhone 3gs. its been factory reset, so I decided to charge it. Once fully charged, i started to set it up, adding apps, and playing with it just as hard and my captivate. The battery sure went fast. I would say it went just as fast as my captivate.