Not using MobileMe. Using Google Calendar and Contacts push through Nuevasync. I don't make that many changes to either my contacts or calendar so will it affect my battery life dramatically?
If changes are not being made constantly, then push is better on battery life than checking manually for changes. Push becomes a battery hog when changes are being made more often, Such as someone who receives 40-50 emails per day, would have battery issues from push. Someone who gets like 5-10 emails per day, would benefit battery wise from push.