A weekend with Olympus last July was my first and so far only NC diving experience (and except for Bermuda my first Atlantic Ocean diving). All my other dives had been tropical or sub-tropical or similar (So. California kelp). I knew what to expect, but it was still an eye-opening experience for me. It was a long and choppy ride out on cloudy and rainy days. I wished I had brought something warm to wrap around myself. (The third day the dive was canceled.) I used a 5 mm and a hood and was thankful for it--73 or 75F on the bottom is COLD to me.
Also, this was my first experience diving with a boat full of people who appeared much more prepared than your average tropical vacation diver. If I recall, everyone had at least a pony bottle, and some had doubles/sidemount, and one rebreather. I didn't see a single jacket-style BC. The crew gave a serious dive briefing--no joking around like I've seen in the Caribbean. Overall, a very interesting and motivational experience.
Also, this was my first experience diving with a boat full of people who appeared much more prepared than your average tropical vacation diver. If I recall, everyone had at least a pony bottle, and some had doubles/sidemount, and one rebreather. I didn't see a single jacket-style BC. The crew gave a serious dive briefing--no joking around like I've seen in the Caribbean. Overall, a very interesting and motivational experience.