i read some good reviews on O'Neil suits but i couldnt pass up the deal i got on mine. the slippery matrix suits seem to be popular too.
Bottom line... the suit that fits is best. A tight 2mm wetsuit will be warmer than a loose 5mm wetsuit. I can comfortably ride in 50-55° water with my 3/2 wetsuit. I'm not interested in going any thicker because the air temperature plays a big factor for me because my hands, feet, and face will be the limiting factor in cooler weather and not so much the water temperature. Just something to keep in m ind.