I ski at hafjell every weekend and the park is great and it has a bunch of nice groomers.
and to the guy who said you cant find powder their i have been skiing pow for the last 3 days even tho its the end of march, you just have to look a little their a lot of open spaces in the woods. But hafjell is not the best place for pow, but if you want a little of everything its great.
Oppdal has some of the best pow i norway if you ask me but last time i was their the park sucked but that was 1 month ago.
You will probably be happy if you got to hafjell, trysil, oppdal, hemsedal, geilo,
If you want Norway's best park but not much else go to Vierli its been really good this season!