Personally, we like Vail. There is a lot to do, along with great dining and shopping.
For summer, there is rafting, hiking, great golf (lots of nice courses), biking, wildflowers, fly-fishing..., but Breck is ok, too.
In winter, there is no comparison. Vail has the best all-around winter experience - better, larger mountain (biggest in USA), lots of variety in ski run choices (trees or open bowls), great ski/snowboard school, better snow, warmer temps, snowmobiling, cross-country skiing, snowshoeing... Having skiied all over the world, Vail is our choice as the best all-around ski destination.
Vail also has unbelievable lights during the holiday season, and is situated at 8,120 feet above sea level.
There are a lot of very upscale fractional ownership units coming online in Vail, although I doubt these would be available on trade.