I'm using the base CM kernel and I haven't done any hardcore testing. But I do work from home and use my phone a lot for conference calls, emails, text messages, web, etc and I normally put it on the charger at night at the 50% range on battery.
I have found that (even after resetting battery stats) the percentage isn't the most accurate. For example, I have used it very heavily before and it would drop to 40% somewhat quickly, but then all of a sudden that last 40% would last a very long time. I know when I was trying to kill the battery for some reset stuff, the last 20% would last as long as the previous 50% sometimes.