We are just back from Konigsleiten in Austria. Further along the valley from Mayrhofen and Zell am Ziller, but with access to miles and miles of piste. It was Dutch half term and the Austrian/German holiday Fasching last week too, so it was a bit busy, but nowhere near as rammed as French resorts I've been in at similar times of year. Our kids' dutch ski instructor told us that next year's UK half term doesn't clash with the Dutch half term or Fasching, so it will be quiet. We only heard 2 other English speaking families all week out there.
We hired a private instructor as our kids were a mixed ability group but wanted to stay together, but if they went in a ski school group the lessons would probably be conducted in German or Dutch. My daughter didn't find this a problem when she was in a group class a couple of years back as even the younger children were keen to practice their english on a native speaker, and the instructors all speak english too.
There was plenty to do too outside of skiing. We went down the toboggan run at Bramberg, which is the longest in the world, and we went on the Zillertal Arena Coaster, which is a kind of semi-lethal bobsleigh on tracks. Great fun! There was also swimming nearby with slides and outdoor heated pools, and night-time snowshoeing treks if you wanted something different.
Mountain restaurants were cheap by Alpine standards, if you like Tyrolean food and lots of wiener schnitzel! The supermarket was a bit more expensive but only because there was only one in town. We could have gone down to Zell am Ziller for cheaper groceries but couldn't be bothered.
I went to Sweden over the Christmas holidays too, and in terms of value for money - cost of lift pass with regard to skiable area, places to eat on the mountain, etc, the less well-known resorts in Austria win hands down. Sweden was limited in mountain restaurants, the swedes seem to mainly take a picnic to eat in warm rooms at lunch time. The food in the supermarkets was eyewateringly expensive and you could only buy alcohol above a shandy in a government monopoly shop (nearest one was 60km along snowy back roads from where we were staying.)
We went to Selva in the Dolomites a few years back too, and I would return in a heartbeat given the chance (just not enough days to ski everywhere I want to!)