Went to Ellmau to ski 2 years ago for New Year. My first and only time to Austria (so far), but we loved it. As NDS says it’s quite quiet, but still a few bars, if you’re going for a family holiday it’s really good.
None of the slopes are too hard, good beginner/intermediate skiing not a lot of off piste. The trickiest runs are off the highest point in the area Hohe Salve. The pass does include Westendorf, but Ellmau is probably the furthest point from there in the area.
Lots of huts on the mountain which serve really nice good value food.
The lift and cannon system is really modern. We were there at one of the busiest times and only had to queue for the funicular first thing in the morning, no other for the rest of the day.