Those using AA are much less fiddly to replace. If they used SUUNTO style battery and replacemet procedures I wouldn't be quite so keen on having to change them as often. IIRC I get around 50-60 dives out of a 3.6v AA on my petrel with each dive being 60mins plus.
I could live with 50-60 dives out of 1 battery, but the Petrel is not right for me.
Right now, I am leaning towards the Oceanic VT4.1. It seems to be going for a very reduced price everywhere. I wonder if Oceanic has a replacement coming out soon.