I mostly agree with aaupgrade. I live in Denver and am up in the mountains as often as possible. The Vail property is a bit nicer, and if you have status (which is not mentioned on your profile) the odds of getting upgraded to a large suite are much better at Vail. However, if you want a property that has more shops, restaurants, and such in close proximity, Breckenridge is much better. Vail has more of everything, but it is much more spread out and you'd really need a car to go to that perfect restaurant you saw advertised. In Breck, the entire town (which is granted much smaller than Vail) is within walking distance... especially in summer. I used to own a condo there (just sold it a few months back) for that very reason... it's an actual town that's been around for well over a hundred years... and you really don't need a car at all while you are staying in town. Both have great access to trails and activities.

Enjoy your stay in beautiful Colorado!