You gotta remember that the DSi has at least up to 5 hours of less battery life as well. Unless I remembered wrong. Correct me if I'm wrong please. That, IMO, is a big turn off.
That is 100% false.
The battery life difference is very little.
Ah okay, thanks for the update. I remembered back then I read from Kotaku that there was a significant difference in battery life. But it was the time before DSi was even released yet.
Nintendo DSi: The lowest brightness (9-14 hrs), low brightness (8-12 hours), medium brightness (6-9 hours), high brightness (4-6 hours), highest brightness(3-4 hours)
Nintendo DS Lite: The lowest brightness (15-19 hrs), low brightness (10-15 hours), high brightness (7-11 hours), highest brightness(5-8 hours)