I doubt the battery is going to vary that largely from one rom to the other. I don't think I'm going to go from 10 hours on one rom to 26 hours on another, wish that were possible but I just highly doubt it. Other than that I don't want a sense rom, even with another Launcher I found there were plenty of other elements of Sense still in the rom. Also all the Gingerbread roms apparently have the voice mail problem, and I can't have that. I tried setting up Youmail as an alternate voice mail but it's not very good either. Unless you let it notify you via either email or text (which results in double notifications) then it can take up to 30 minutes to notify of a voice mail as well.
I think most battery estimates completely depend on the user. If your phone sits on your desk for 25 hours 40 minutes of the 26 hours then yeah I can see it lasting that long.
When one 15 minute phone call uses up 25% of my stock battery, then that's just bad.
I'm really beginning to question if my stock battery was defective though. Today is my first day on the extended battery, and after being at work for 7 hours, using wifi hotspot for 2 hours straight, browsing the web a bit on the phone, display has been on with auto brightness for 45 minutes, the extended battery is at 64%. I expected the extended battery to be twice as good as stock, this thing is about 4 times as good as my stock battery was.
I'll have to decide if the extra bulk is worth it though, and may check with Verizon to see if I can get the stock battery exchanged under warranty without having to exchange the entire phone, just to see if my stock battery was defective.