I live in NY. B&H is a great place to see and play with camcorders. They sell UW housings, but they aren't really knowledgeable about them and don't have them out on display to play with. If you are going to make the trip, I would call in advance and ask if they have the housings in stock and available to see/touch.
Is there another place in NY that stocks housings and knows stuff about them?
Honestly the only reason I would choose one camera over another is based on what sort of housing features it would allow. And the only reason I am interested in the camera in the first place is as
1. another service to offer dive customers,
2. and/or to get fill-in work on days when I have no customers of my own (I could work as guide/instructor for other operators, but I have done that to death)
3. and/or to use as promotional material for my dive operation.
4. and/or Shooting 'stock' footage for customer video and promo material. (It's hard to guide and shoot at least in my experience. So I'd rather go out and collect footage on no customer days, and just add in some customer shots, instead of trying to shoot them all dive long, and trying to turn that into something worthwhilw for them.)
From what sjspeck has schooled me on, and the further research I have done reading around online, it seems that HDV is the way to go, from the editing perspective. The fact that Sony's have LANC means that the camera is semi-replaceable, so I think I have decided on Sony. But I only choose Sony because of the housing features.
(I won't ever use this topside. I used to play around with miniDV, and found that I am simply not a very good story teller, as far as shooting goes. I tended to do more editing with found clips imported to DV than with footage I shot. So the camera will be dedicated to UW use, where the story is the dive.)