I am gonna agree with Lonerider on this and recommend the SL. I've owned the SL, Heritage and now ride a Cobra. The SL is a fantastic deck that is good on groomers with great edge hold while being ok in powder and still playful.
I demoed a proto last year and it was a good deck but not as damp as the SL and more freestyle oriented.
If your looking for all mountain/freestyle = SL if you want freestyle/all mountain = proto.