We stayed in Zell am See before Christmas as a family of 4 (two kids 12 and 8) and really enjoyed both the atmosphere of Zell with the lake, shops and Christmas markets and how easy everything is from getting there by train (1.5 hours from Salzburg) to the modern and efficient lift and cable cars. Skiing is good and reasonably varied with options for different abilities across the three ski areas and as its high the snow was decent even in mid December. Worth going to the top of the glacier for the view and being able to ski all the way down although it does take a while and lots of cable cars/lifts. Would recommend Brundl sports for hire as great quality (and brand new) kit as well as really helpful staff.