So I have the D6603 and am using it on AT&T, I've had no complaints thus far. I had the Sony software update pop up today and I'm pretty gun shy about updating with the reports of battery drain. I am hoping to get impressions from those who have updated, how's your battery life been? Any better? Worse? Anything both good or bad would be great to hear. Also does stamina mode actually work? I've always had it on but some say it's better to turn it off.