Laura opted to go with a full drysuit. It creates a watertight seal around your neck and wrists and in theory keeps you a lot warmer in cold water. The downside is that a dry-suit is more complicated, more expensive, harder to maintain buoyancy (at least for a drysuit beginner) requires you to wear a lot more weights (to offset the air in the suit. I really disliked the choking feeling from the neck seal, so I opted to wear a wetsuit (varying in thickness from 8mm - 5mm). Water on the surface wasn't too bad - even when we hung out on the surface for 30 minutes waiting for everyone to get properly weighted etc, the cold wasn't too bad. But at the bottom it was cold - only 11°C!! Both Laura and I noticed that we moved and functioned considerably slower in the cold water.
What did we get to see? On the surface, we saw an otter, a sea lion, and pelican. Down below, there were lots of pretty big jelly fish, nice anemones, fish, lots of kelp -- an a friendly seal that came by to check us out! Visibility wasn't great -- I'd guess about 3m or so. And because it was so cold, our dives weren't too long - around 30 minutes rather than the hour we'd generally do in warm water. On the surface, the rocking of the waves on the little zodiacs was pretty unpleasant -- I think most of the people on the boat were feeling some degree of seasickness.
Not sure how often we'll be braving the cold to scuba dive out here in the future. It's a very unique marine environment, but its a lot of time and effort for the fairly short dives and the cold a low visibility make it a bit less rewarding.