A lot of people I dive with tried the Weezle wear - many loved it and stuck with it, some found it rather bulky, didn't like the fact that you need to add more add to the suit to create the loft needed for warmth, and found that they needed to add more lead.
I liked the Weezle wear, and didn't find that I needed to add much air or any extra lead (although I am a pretty small/lean fellow and don't wear much lead to begin with).
I switched to the Fourth Element Arctic two seasons ago (because the LDS I teach for carries Fourth Element and not Weezle). I have been very happy - no bulk, different sizes of tops and bottoms (I am bigger up top - thanks P90X - than bottom). I recently tried the SubXero on an ice diving weekend and was impressed with the warmth and comfort of this suit.
I dive in a White's Polarflex drysuit, which has 2mm crushed neoprene on the bottom and a trilam material on the upper torso and arms.
My advice? If you can, try/borrow some before you buy. For most people, it seems to be a matter of preference depending on their body size, tendencies to get cold, suit material/design, diving needs, amount of air in suit, etc.
Just my two cents...Cheers!