I'm a west coast diver (50% of the time ish) and Argon works enough for me. It can be pretty warm outside and down right cold in the water. Really warm undergarments make you sweat like a fat kid then that moisture negates that undergarment in the water. With argon I can run a light garment without sweating too much and feel warn in the cold. I keep a larger bottles of argon in the truck and purge my suit a few times as well as valve off some moisture. YMMV