Nakiska was the best for jumps a couple years ago, Then Clayton left... it just hasn't been the same.. in my opinion.
Canada Olympic Park's Jumps were the best they've been in years, at least i think they were, and they have an okay selection of rails; the only drawback is it's very rare to see a lip up to the rail, it's all buttered.
As far as Sunshine goes, it's my favorite place to ride, however their park is lacking. I think they have the widest selection of rails though, and their usually fairly well kept. Also, their lift set up, in my opiniion, is by far the best of any of the local hills... Louises' just pisses me off, they're all so fucking slow.
Overall, I think Louise was the best, for park anyway. They had a good selection of rails, from small ride on boxes, to some larger rails, with smooth ride ups. Their jumps were the best in the region, some fairly big ones, nothing HUGE, but still made for a super fun day.
Although, now that i think about it. As far as size, selection, and difficulty goes. Fernie had the best park. Only it was situated in a fucking awful spot. A 15+ minute quad chair ride, to the park, then a 10 minute ride back to the chair from the park. If you have a Snowmobile/knew someone at the hill, or were stoked about hiking for the entire day, then it's amazing. It had by far the biggest, sickest rails in the region, widest selection as well. As far a jumps go, they had the most unique features, from some massive butter boxs which double as pretty huge hips, to some fun step ups, they had it. If you're looking for your basic tabletop/jump, they didn't have the biggest, but they had things other parks didn't. If they install a lift that caters specifically to the park, then it's totally worth the 3 hour drive from Calgary. There's also some sick BC, and some nice spots to build your own kickers into some deep powder.