JeffG:2: Buoyancy Characteristics/Real Life weight Ratio. BP is way ahead in this regard.
3: Crotch strap. My Jacket BC always slipped up my body when floating at the surface (a part of being tall and skinny I'm thinking)
I don't want to be picky but my Transpac (presumably one of the others!) fulfils at least these two conditions - as I presume most back inflate systems without a plate would.
Should this thread really be about back inflate vs jacket style?