Mikey,

I haven't seen one in the flesh, but I have read the specs on the SW20.  I'm a SCUBA diver as well, so I'm always on the lookout for new SCUBA-friendly photo gear.

The one word of caution I'd have about the SW20 is its depth rating.  From what I've read, it IS waterproof, but only to a depth of 5 feet.  I just doesn't have adequate seals in it to withstand the pressure of typical recreational dive depths (50' or more).  This might be a fun camera to use with the snorkel gear, but I think its use in SCUBA is pretty limited.

Chris