FERNIE is only fun when there is snow and they open stuff up other wise I would steer clear. Not sure what it's been doing as i haven't check on it in a couple weeks. Fernie can also get hella cold compared to the other two which usually offer warmer temps more often in my excperience. As for park Fernie has no jumps just rails and last time I skied there they weren't set up well.
BIG WHITE is super fun tree skiing which is good because it does have the nick name "big white out". There is also some slightly "more challenging" terrain in the cliff bowl if its open, but both times I was there last year it was closed, but if it's open there is some fun lines in there. Big White also has some pretty easy to get to slack country that can result is some sick runs. As for their park I haven't rode it this year but last year they had some fun rails and they where set up fairly well it was also nice to see their jumps on the bigger side from past years Ive skied there. BUT I will tell you that the jumps last year had shitty spacing and super sniper landings so you had to really be on your game for dialing in your speed. On another note everything being ski in ski out pretty much is a sick bonus!
WHISTLER/BLACKCOMB, well there is a reason so many pros and aspiring ams flock there. As for the mountain riding experience they get 35 feet of snow a year on avg, and there is tons of terrain.! They have tons of sick slack country and some pretty gnarly inbounds stuff to like the famous Air Jordan and Whis and the coulouir on Black. And despite popular anti-whis beleifs you can still find fresh snow several days after a storm with out much effort. As for their parks, they boast the biggest and in my opinion the nicest shaped jumps in Canada and from what I've heared the best 22 foot pipe too. They also have an ass load creative and progressive jibs. I mean the length of the parks on there own is rdiculous, I'm pretty sure the Whistler park is over 1600 ft vert. As for apres the village is sick with lots of choices for food and drinks and looking at gear. Also Whis propably has the highest percentage of girls at it (and by a wide margin) of all the resorts Ive ever skied.