"What's it like?"
I found Mayrhofen a great blend of relaxation and activity. During the day you have a wide range of mountains and courses to ski or snowboard and can indulge yourself with a beer or food at the many restaurants as everyone flies by.
The town itself during the day has quite a relaxed atmosphere and slow pace of life and has decent shops and restaurants. During the night it can be a fun place to go out with plenty of lively bars and pubs.
If you fancy a change of scenery then you can catch a train to either Salzburg or Innsbruck and take a wander.
The facilities for getting around are good with plenty of buses serving the slopes and the train station easily accessible.