I'm big on the Bare Arctic and the companion 7mm hooded step-in shorty. I've used it to 40F and I never get a shot of cold water. By the time water reaches me it has warmed between layers. The gasketing does a great job at limiting water exchange.
FIT is ctritical. A hint of compression all over is what you want lt have. No sags or bags and few to no wrikles. When I remove my suit after a dive the witness marks of the stitcing remain imprinted in my skin for a while. Meanwhile it must not hinder you inhaling or assit in exhaling. Arms on opposing shoulders, reach for the stars, touch your toes, all unencumbered.
A good, well fit 7mm suit with 2X on the core is not as evil or uncomfortable as some will suggest. There will come a point where going dry is desirable but everyone can't go that way out of the chute. Also personally I much prefer diving wet while the season allows so a wetsuit will not be obsolete for me. I went dry last year and just returned to dry diving a few weeks ago.
Pete