Some say that Kirchberg is a smaller, quieter version of Kitzbuhel. The two are lift-linked, but Kirchberg is a resort in its own right. It's a largely unplanned village, lively and crowded, with lots of young Germans, Scandinavians and Brits here to enjoy the nightlife. It's quite attractive and the hospitality is excellent. Prices are generally lower here than some more mainstream resorts in Austria, although they are still comparatively high.
The ski area has an excellent range of long red runs and challenging blacks, as well as some decent blue pistes for the less experienced skiers. Boarders have a specialist park and a half-pipe, while 'langlaufers' have 40km of trails. Because of its link to Kitzbuehel, there are occasional queues and the bus to the lift can get crowded, as well as car traffic in the village. If you want more skiing, you can always invest in the 'Kitzbuheler Alpen' pass, for nearly 700km of unlinked pistes. Accommodation and eating are mainly hotel-based, but there are some excellent mountain restaurants for lunchtimes.
Overall, Kirchberg in Tirol is a good alternative to Kitzbuehel with great nightlife and accommodation.