I don't know all that's out there, but I've been impressed with Mustangs suits.
http://www.mustangsurvival.com/
What you should consider:
- How long do you expect to be in the water?
- How cold is the water?
- Is the suit comfortable/durable enough for constant use?
- Do you need additional flotation or do you want that from the suit?
I say this because we carry a dry suit with a thermal liner, gore-tex socks and rubber neck/wrist seals that is extremely good at keeping people alive. However, it's hot, uncomfortable, knees wear out for the GIBs, and it provides more protection than is needed in the summer. The result of all that is that most of the time our suits are sitting in a bag in the back, ready for us if we're planning on extended overwater/offshore flight or if engaging in a risky over water operation. Because of this we're looking at a more comfortable and durable suit from Mustang that will be worn more frequently. A suit that provides less protection is better than the suit you aren't wearing.
You should also consider signalling devices. Being able to stay alive in freezing oceans for six hours is great, but if the rescuers can't see you... I'd recommend a sea dye marker because it's visible from relatively high altitudes and it can "deploy" on it's own. Problem is it dissipates, especially in moderate or greater sea states. There's also a floating streamer from Rescue Technologies that looks promising
http://www.seerescue.com/ . It's visible at lower search altitudes, so if your position is approximately known it works well.
Of course, a radio/beacon is the best signalling device to get the rescuers close and then a strobe light to get them on the spot. I think it's nice to have signals that don't rely on batteries.
Matthew.