It depends how you use the phone. Android phones can last between 5 hours to 3 days. It all depends on usage. Just because you heard or experienced 1.5 days of battery life with iPhone, and then you heard somewhere else that Droid X2 stayed 5 hours on a charge, doesn't mean the iPhone's battery is 3x better.

Games or heavy wifi browsing can easily eat into your battery life in several hours, regardless of the phone.