When I saw the pics I said the same thing...Then I saw the thread was 3 pages long and I skimmed through to see you asking the same thing that I initially thought.
Yea, those yak tops are an interesting peice of apparel. I don't know how they compare to wearing an actual dry suit (scuba) but the neck peice gets real old real quick! It's a solid rubber band that cuts off circulation to your head, basically! So aside from coming up to quick, you already feel pretty fuzzy!
However it's better than the pinch you get from a vulcanized rubber suit!