We visited the resort in April 2010 (1st ever ski trip) and then again for Christmas 2010. We're planning a 3rd trip this coming April. It is a great beginner resort with decent groomed slopes, no nasty surprises or random piste classifications (i'm looking at you Val d'Isere!), lots of ski in-ski out, excellent equipment hire and generally very quiet (certainly when compared to the Alps).
Now that we have been to the Alps and skied Espace Killy and Paradiski, we can see the limitations of a resort like Hemsedal. It's not large and it would be a little tame for good intermediates/advanced skiers. We'll probably concentrate on the Alps from next season, particularly as we are seeking greater piste mileage and variety.
The snow in April 2010 was excellent and the whole resort held up well. We struggled a bit in December 2010 as the snowfall was poor at the beginning of the season. It was very cold though.
Apres ski is quite limited but the food in the restaurants is good (although fairly expensive).
Some photos below:








