I have around 700 days on my 2001 Premeir and it still rides like new. Beat the fuck up but still rides like new. Can't comment on the newer boards other than to say the base material on my proto is much thinner than my premier. Had a huge core shot on the first day with the proto. I can't say what the damage would have been if it was my premier but I've nailed so many rocks with that board and everytime I had a hard time finding the damage on the base. I sense that is not the case with the proto.
I have much less days on my 2010 Premier. However, I just spent a week in Jackson Hole which still had some thin cover in areas and I nailed a bunch of rocks and boulders nearly every day. It still has nothing but surface scratches. Only 1 bigger gouge near the edge that I may have to keep an eye on.