Thanks Stuart, I'm probably ML an though.
Tell me why the XCS2 is uncomfortable on deck in warm weather. Seems like a Fusion and XCS2 both with suitable undergarments for the same water temperature would feel equally warm out of water too. Is there something about the compressed neoprene that is warmer out of water?
I don't know about a Fusion, so no comment on that. My comparison is to my other suit - a Waterproof D9X which is a fairly light, breathable tri-lam (they call is a quad-lam).
During the summer around here, air temps in the 80s and 90s are normal. The quarry water is around 38 - 39F at the bottom, at the same time of year. Gearing up for 38 degree water, when it's 90 degrees out is always going to be a bit miserable. But, the XCS2 is heavy, doesn't breathe, and adds even more (unwanted) warmth, compared to my D9X. I wear the same undies under either suit. Maybe that means the D9X isn't quite as warm in the water and so this isn't a totally apples-to-apples comparison. But, I believe (it's just a gut feeling) that even if I added another thin base layer under the D9X, to make it apples to apples in terms of warmth in the water, the D9X would still be more comfortable on the surface because it's breathable.
If I'm geared up and it's in the 80s out, depending on what water temp I'm prepared for, I can still be very comfy standing around in the shade in my D9X, but a sweaty mess if I were wearing the XCS2. Cool to cold air temps and cold water? The XCS2 is great - if you aren't flying any time soon after. Warm air temps? Need to fly with the suit in the next couple of days? The light, breathable shell suit is way nicer.
Plus, the trilam is easy and comfy to take the top off, tuck the arms through the suspenders and continue to wear. I have the suspenders for the XCS2, but it's definitely not as comfy to doff just the top and continue to wear. That is partly because once you get out of the water, the suit is wet, making the top even heavier than it is anyway, so tucking the arms through the suspenders doesn't work as well because it's so heavy it wants to try and fall off constantly. Plus, the exterior of the XCS2 holds water more than the exterior of the shell suit does, so tucking the arms through the suspenders gets your undergarments way more wet than doing the same thing with the shell suit.
The XCS2 not having a telescopic torso means it's also much more of a contortionist act to get the top on and off. Especially if I'm wearing my cold water undies. The D9X torso telescopes, so taking it off just means lifting it straight up over/off my head. No contortions required.
I wore the D9X on a NC boat last Sept. I was diving steel doubles and wanted the redundant buoyancy. The surface conditions were awesome. It was a warm, sunny day. Between dives, I kept the suit on. I didn't even peel the top down right away. If I didn't go hang out in the direct sun, I was totally comfy. With the XCS2, I would have gotten completely out of the suit as soon as I got out of the water. And waited until the last minute to put it back on before the next dive.