Hi Alton,
I had an O'Neil PyschoFreak 6/5/4 before buying the Ocean Rodeo Soul. IMHO no comparison between the two in terms of warmth. I had two SUP sessions on the South Thompson this December in -10 temps without factoring in the wind. Pretty awesome to SUP down a river gliding over the sand bars in the snow
No need to worry about the deck freezing over without any spray.
I'm still not sold on the Soul in waves despite what the reviews say. It's a great suit for Nicola and Centennial type conditions but I will keep it away from waves at JWSP and the Coast for now until I see how it fairs after some hard crashes.
As for the mitts, I use Patagonia's R5 Lobster mitt. No arm pump and great for swimming after your gear in high wind conditions in Azerbaijan. I've also had these down to -10 without any problems. They are lined with Merino wool on the inside and are the warmest, functional, mitts I've used so far.
Cheers,
Chris