AR6s are pretty much a stock park and pipe ski, from what I hear they ride very nicely throughout the park and pipe, as well as down the groomers, through the trees, bumps, and even in 6 inches of fresh. They are supposedly very light, poppy, stable, and pretty durable.
The Alpha 1 is a new breed of park skis, with its early taper, rockered tip and tail, and regular camber and sidecut under foot. Its supposed to be very light all around and also in the air, giving it very low sing weight. Its also supposed to be great for taking off switch and carving off lips, as the ski is much less likely to hook or catch due to the rocker. Might not be they best ski to take onto rails, boxes, tires, barrels, etc as it has the race base like the pipe cleaners, whoch will make it nice for clearing large hits, and just cruising around the mountain, but is much softer and could get wrecked on rails.