I just returned from a double weekend at JH
First time 2 days, then went for 3 days
First of all, I am a novice at carving. So keep that in mind while reading.
First time I was there mid February snow was compact, I sticked to double Blue runs (equivalent to backs here in the east) as I was with my 10 year old son (intermediate skier)
Most of the time we rode the Apres Vous and Gondola. Many groomed trails but also many MANY traverses which are a real pain in the butt (narrow and long, going from one run to another)
Second time I went beginning March was with some friends, temperatures during the day were high, softening - if not mushing the snow - then freezing at night. Took a lot of work from the staff to make runs decent on 1st morning, but they did a great job. We did a few black runs (double diamonds in the east). By 2 pm I was shot. you ride at 10,000 feet, get winded easily. runs are steep. I mean STEEP! For my level makes carving hard., I don't have the confidence and mostly was riding traditionally (no carve).
Second day snow sucked (almost in the 60's!). Took a very bad fall on second run, bent the bail on my rear foot, boot was far too loose and had to stop not feeling comfortable
Lift ticket was $130, rentals are also expensive, $140 for 2 days
Food is also expensive
View is spectacular
Runs are tough. There are a few groomed runs, but if you are into the steeps, they are not groomed and become quite bumpy by mid day because of all the noobs ( like me :P ) that are concerned about diving down these steep runs. It gets also crowded, the good skiers are zooming fast all over the place, and the " easier" runs are packed with the beginners and intermediate. look online there is a nice interactive trail map
It's beautiful, and if you are confident and good it's probably a lot of fun. But in my opinion for a intermediate and below, I would not advise.