I use two 161's and have been very happy with them. I use my stuff mostly in very cold water (39° - 41° year round) and they have performed flawlessly. They are heavy, but 99% of the time, I am not flying and that's the only time it matters.
I think that one advantage of the large battery is the speed at which the strobes recycle. My typical shooting technique is to shoot a series of shots in rapid succession... and these strobes are always ready. I don't pay attention to GN much, only because most of the time, I'm using them at half to 2/3 power.
I have friends with S&S strobes and my two impressions are that (a) in a week-long trip, you would need so many AAs that the spares probably weigh as much as the Ikelite battery packs, and (b) from what I have seen, the battery compartment is poorly designed and the door is a likely failure/flooding point. I know of two cases of this happening in the past year, although one of the guy is really bad at maintaining his gear, so it was likely "user error" !