As long as I don't use my E4GT with the newer modems, then the battery seems to last forever. I unplugged at 6AM this morning I am still at 81%. But I have only used my phone 15 minutes all day. However, if I am stready using my E4GT, battery life has been pretty lousy in general on FD05. Running between 70% and 85% the amount of time it ran on EL29. But definitely not prohibitive, just noticeable.
However, I am now not having any bug issues on these last builds. Very happy. And now that I am used to ICS, I cannot go back!
Robert