I can’t compare anything to an iPhone, but I can report on my Android after about six weeks of use.
The battery life specs, according to the User Manual (PDF here), are
Rechargeable Lithium-ion battery: Capacity: 1150 mAh
Talk time:Up to 350 minutes for WCDMA
Up to 406 minutes for GSM
Standby time:Up to 402 hours for WCDMA
Up to 319 hours for GSM
(Approximations based on the phone manufacturer’s lab tests.)
I have found the “talk time” spec to be reasonably accurate.
I include in “talk time” using any feature which causes the screen to come alive, such as the 3G and EDGE connectivity, the camera, or the ebook reader.
For example, last night, when the battery was down to about 30%; I spent about an hour and fifteen minutes mucking about at Project Gutenberg downloading some books; by the time I was done, the battery was about 15% and the phone was displaying the “charge me now” message.
I really have no way that I can test the “Standby” time by itself; I’m not in a position to leave the phone sit for days to see how long it lasts.
From a practical standpoint, it’s comparable to my old T-Mobile Dash (now recycled): When I use it heavily during a day, I have to charge it that night or early the next morning; otherwise, I end up charging it every other night.
On the downside of maintaining battery life, using this phone is so much more fun than using the Dash that I’m having to charge it more often because I’m using it more; I’ve even read myself to sleep a couple of nights with the ebook reader.