Well, my W3s came in today. I went with the L to start as that was what the size chart said should be closest of the two. Bingo. XL still in box and will just go back - no need to open it.
I would prefer it if it was a little snugger in the hips and the neck was 1/2" shorter (probably not actually size related, just style) , but my arms and shoulders fit and I can bring my arms forward! Everything else is fitted but not overly snug. I probably could squeeze myself into the ML, but I would likely feel perpetually squeezed. I'll sacrifice a touch of warmth for the ability to actually move comfortably.
My takeaway is that (at least in L) the W3s run pretty true to the size charts and are actually cut for "average" humans, not twigs.
The neoprene seems comparably stretchy to the definition and, as listed, a bit thicker.
The lining is nice and seem like it will make wet don and doff easier.
Ankle and cuff seals are very stretchy and easy to get on and off. @ 7+ inches long, there is plenty of depth to sandwich tall boots and gauntlet gloves between the inner seal and the outer shell.
In-room the W3 seemed slightly less warm while on - admittedly different locations. I attributed it to the IR liner on the Definition, but when I peeled off the W3, I was just as sweaty. I think the cloth lining on the W3 made it feel less noticeable.
I'll try to remember to report back next month once I've had some dive time with it. Thanks for the input, guys!
