For instance I had a Razr, I was chewing through battery life so got the Maxx. No issues from there on out. I get relatively poor reception where I sit in my building so it sucks more power up to get a signal.
My wife has a Razr that is running this ICS as well, from 5:30am til 6pm at night with about 1-1:30min of screen time she sits at 50% battery, goes down to 35-40% the remainder of the night before plug in. Though most apps she uses is not intensive, she has very good line of sight to towers and gets great signal. As well at home switches to wifi network and disables the data connection.
Now mind you as soon as I got my Razr I was on the ICS within hours. I don't know how GB was and don't care to run it. It will be great when ICS officially releases and maybe since this is a test that more systems will be tweaked for the phone.