Lift count :
5 x Chairlifts
2 x Drag-lifts
2 Magic carpets
Ride area 470 acres/34km
Buttermilk is probably the weakest of the 4 Aspen Mountains but it does play host to the Winter X-Games, so things can't be too bad.
The area leading from the main base is home to some nice easy beginner runs, veer off a bit from the top of the Summit Express and you'll be faced with a 1.5km continuous terrain park, filled with rollers and hidden features in the trees. It also leads to the main Crazy Town terrain park, and at the bottom that absolutely monster halfpipe that is used in the X-Games.
More advanced runs are found off the Upper Tierack chair, but the runs are pretty short generally.
Buttermilk is one of the better areas for learning on and rarely gets busy, but more advanced riders should head to the other mountains. If its terrain parks that get your juices flowing then you can't really go wrong here.