Big White - Big selection of skiing (sub-alp, powder, park, gladed, etc) and a decent park. Large mountain with many chairlifts so less lineups.
Silver Star - Not quite as big as Big White and not as much selection of skiing. Wicked sick park though, everything's perfect everyday because our park crew works super hard for big features. Less chairlifts.
It all depends on what type of skiing you plan to do, I guess. When I'm not feeling park I head out to Big White.