It is a family friendly town so you will see quite a few kids. At night it turns into more of an adult town. I would recommend a visit even if you are wanting to be kid-free.
The time of year you are visiting will drastically impact the things to do here. Hiking, biking, white water rafting nearby in the summer and fall. Skiing, snowboarding, dog-sledding, snowmobiling in the winter. The food is exceptional in Vail, so if you are wine lover or a foodie you will have a blast. Vail is a bit more pricey than some of our other mountain towns, so be prepared to spend some money.