(this is from my review of the regular width Proto HD board)
I was able to demo the hell out of this board last week up at Brighton, UT and I was seriously blown away by the Proto.
Right off the bat, I could tell that the sintered base on this board was FAST, it felt like someone was pushing me down the hill.
Another stand-out feature was the CDS dampening system. Where other boards might slip and slide around, the Proto grips the snow and slices through crusty, tracked out snow.
The true twin shape makes this a blast to play a round on. A medium flex is supportive enough for when you're craving the need for speed, but will still allow for playful jibbing. Reverse camber between your feet gives you the playfulness while the positive camber outside of the bindings gives tons of pop.
If you're looking for a board to do it all, you should definitely keep the Proto HD in mind.