Steeps, Snow, lack of crowds, Challenger lift, tree skiing, the SIZE!
The flats coming down lone mountain can be hell for boarders, Remote.
Big Sky is an amazing place to ski. If you haven't skied there and have even the slightest interest in going, I highly recommend to get off of the fence and go. The terrain off of Lone Peak Tram is pretty good when it's not in a Blizzard. The snow off of the top is typically very good and the terrain has constant steep runs flanked by rocks (or chocolate chips) on either side. These runs off of the tram can last 20-30 minutes if you plan on going down to Swiftcurrent, almost 6 miles of steep thigh burning skiing followed by open bowls and then blue cruisers to the base. However, I recommend staying on the South Side when you get off of the tram for the incredible glade skiing and above average absence of crowds.
Crowds are NOT an issue however. I have been to Big Sky during Spring Break and the holidays and it is only slightly busier than a weekday in late January. Nobody comes here for some reason. Couple the incredibly small amount of people with almost 4,000 acres and 23 lifts and you can have not only entire runs, but entire lifts to yourselves.
The best skiing at Big Sky is straight off of the Challenger lift, perhaps one of my favorite lifts anywhere. The Moonlight trees and Little Rock Tongue and Big Rock Tongue always seems to have more powder than anywhere else, and the terrain is steep, and consistently pitched. The trees, oh God the TREES! Big Sky's trees are some of the best I have skied anywhere. There are tight trees, spaced trees, steep trees, open and gently sloped trees, tree runs with moguls and tree runs that haven't been touched since it last snowed 6 days ago. I haven't been to Steamboat, but when I go it will be judged by Big Sky's standards.
The Nightlife at Big Sky doesn't matter to me, because I always retire in Bozeman anyway, but it seems like a very quiet town. There's the typical swimming pool and hot tub fare, and maybe a bar or two, but nothing too lively. If you plan your day at Big Sky right though, you will be too tired to do anything beyond eating a hot dog, taking a soak, and passing out from steep and deep exhaustion.