Why not visit both and decide which you like more.
For those saying a car is essential in Breck, you're completely wrong. If you have a spot in town/walking distance to Main, you're good to go. I drive basically to two places, the movie theater in Dillon, and City Market (because I don't like carrying groceries, not because there isn't a grocery store close).
Also, the Summit Stage is 100% free and runs all over town and between a few resorts (Breck and Key, Breck and Copper, etc.) as well as into Frisco (Walmart) and Silverthorne/Dillon (Outlets, movies, Target). I have a jeep, and I'm glad I have the option to drive, but I know many people who rely exclusively on public transit and it's totally doable.
I'm not interested in the "versus" aspect of this thread because the reality is, especially seeing as how you've never been out west and are from the ec, either would be an absolute blast.
All this talk about "the locals are cooler at X" is a joke. In my experience, people living life on their terms are happy and gracious.