A very interesting topic since booking a vacation in advance or picking a resort to ski at for an entire winter really is a guessing game involving lots of luck when it comes to skiing powder. Just about every resort skis great with fresh snow but even the resorts with 400in. annually have more non powder days than powder days, so how a mountain skis when it hasn't snowed in a week is critical if you are skiing every day.
My choice is Sun Peaks because it has noticeably drier air and drier snow than just about anywhere including Utah, so even when there is no new snow there is a low moisture, very easy to carve snow pack. SP also has some long, wide, go as fast as you want because you are the only one on the run, cruising black and blue runs. With 3600 + skiable acres, SP is Canada's third largest ski resort but it is not the third busiest in terms of skier visits so this means less skier impact on the snow pack.
My biggest problem when I go to other ski areas, especially in the USA, is getting accustomed to skiing with other people on the slopes.