I dive a Whites MK3, which is pretty warm, but it is quite bulky. However, it is not as stiff as the DUI 400g (the old one) so I don't mind the bulk so much.
I have had folks tell me the new 4th Element stuff (the stuff with the shiny exterior) is warmer, but it is extremely floaty. People who have used Weezles have had to add weight to use the 4th Element. Since I constantly try to fight two battles -- warmth and weight -- I haven't been willing to go there. The Mk3 with a 200g Thinsulate vest and argon has worked so far.