I've got a 3 x 2 hyper freak (bought on sale) and its awesome but not even one season and the stitching is coming undone a bit and its starting to flush water / balloon on the legs, cos the suit is soooo stretchy and zipperless so you're stretching that neck area to get into it. Not sure how the 4 x 3 would go after more than one season, but if its one and done, you'll be sweet, if you can get it on sale. I'd buy a hyperfreak again but only on sale.
If you're dead set on an oneil and cold water the other option is the psychofreak which is really warm but also stretchy (less than the hyperfreak but way more durable)..I've had a 3 x 2 for like 3 winter seasons and its holding up great (unlike my old flashbombs which seemed to fall apart immediately or needed to be re-stitched).
If you want some more budget options for cold water, swellnet had a good thread on suits as well from an ex wetsuit designer giving some good info:
www.swellnet.com/forums/wax/392028?page=1