College passes are the same in price. Crowds are bad at either location.
Snoqualmie is closer and the roads are always in driveable conditions. They do have the best park in WA. But its low, the terrain sucks balls (except for Alpental) and its ski school central. Get used to rain.
Stevens is higher, and thus gets snow more often than Snoqualmie. Its got better terrain than most of Snoqualmie, even more if you dont mind a short hike. The park is usually a disgrace. When it snows hard, expect the power to go out, and the roads to be an absolute nightmare. Also expect an hour of sitting stopped on US 2 near Sultan if you leave at the end of a day when night skiing isnt open.
All in all, Stevens is worth it because of the snow and the accessible terrain. Alpental is good, but hit that in the spring when they offer cheap lift tickets, and ski twice the amount of that kind of terrain at Stevens. every day, in better snow conditions.