I am sorry to disagree, but the ICS update caused a nonstop 8%-10% drain on my battery. I monitored it with Bettery Battery Stats and the prime culprit seemed to be the Wifi. Also there were a host of minor issues like text wrapping in the browser (easily fixed by changing the settings), home button lag on waking up (could not fix), general lagginess in responding to swipes and taps.
Finally the only solution I could come up with after 4 days of time wastage was to root the phone, and flash it back to ginger bread where I have rock solid battery life and responsive buttons and swipes and taps. Having rooted it, now I've frozen everything that looks like something that might "update" (ha, ha,) by phone.
I will NOT be renewing my Sprint contract after this eipsode. I'm going prepaid. At least if your carrier takes a dump on you, you can leave without penalty, plus it is much cheaper every month. Lesson learned. Dan Hesse can explain why Sprint continues to have post paid subscriber churn.
I got the upgrade last week and it is working very smooth. HOWEVER, over the weekend, I was able to check on my battery life and consumption. And it is VERY high. I am not a power user by any means. First off, I replaced my OEM battery with a Sedio 3200mah unit as many times I am not near a charger or able to get to one. Over 24 hours, the phone used 60% of the battery That's 1920mah in 24hours, 80mah/hr or 1.33mah per MIN. AND that is sitting idle most of the time. During that 24 hours, I made 45min of phone calls, 15 min of WiFi, and 10 min of games. Before teh ICS Upgrade, I could do the same on the OEM battery (1800mah) and have 25%-30% left. This is a MAJOR problem that needs to be rectified ASAP.
I am in Atlanta and am having ALL the problems listed by "mrcminnesota" and other posts, with the added issue of the phone getting extremely hot while charging.
Some of the new features of ICS just need some getting used to the changes, but having my Favorites icons on HUGE with no way to change their size is a real PITA and so I do not like that change. Called Sprint Tech [level 2] support & got a guy with this phone himself, but he said no way to change those icon's size.
The battery drain is ridiculous on WiFi and not much better on 3G (and I have an Airave at home & still get lousy speed on a 12 g internet connection) since the ICS update.