We stayed in snowmass, but took the free bus over to Aspen one day. The fact that we only came over one day says it all really. Snowmass was much better
Its a very small resort, with basically one mountain, with two ridges and a gully between them. All the runs therefore end up being very much the same.
If you are in Aspen for skiing, rather than wanting to be seen in Aspen, I suggest you use the buses to ski in Snowmass or highlands.
On the plus side, lifts were efficient and there were no queues. Snow was excellent.