I currently have a Kokatat Gore Tex Meridian suit in a size large. It's a great suit, but it's cut to be very roomy. I've found that Stohlquist suits fit more closely and have ordered a Maytag in size med-lg.

Why is this important? An overly large suit will trap a lot of air in it, no matter how much you try to force it out. When you try to roll, the air in the suit can prevent you from going all the way around. It's very disorienting to be looking for the surface (light) and see nothing but the bottom or the deep water (dark). If you have the presence of mind, you can shift the paddle around and either roll up on the side you capsized on or do a reverse roll, but I prefer to eliminate the problem at the source, rather than trying to compensate for it.

BTW, when you order your suit, get it with a relief zipper.