While the excellent groomed skiing gets attention, most people don't know the extent and variety of the lift accessed side country, it's truly excellent when in condition. Additionally, there is nearly endless (and empty) backcountry skiing from 5 to 45miles away. Everything from massive alpine couloirs to empty cruisy powder fields. And all of that terrain gets 2-3x the snowfall of the resort (particularly) further north. 90% of my backcountry tours I don't see another person or cross a track.

Last but not least, Ketchum/Sun Valley has one of the few actual ski towns in North America. A real town, with a great laid back, fun vibe, is walking distance to the mountain itself. Free buses around town make a week in Sun Valley one of the most accessible apres towns I've ever visited.