“To the UK guy,
Either resort will be a great holiday. I used to work @ BS and loved it and it's people, but I think JH is more worthy of a trip from across the pond. More restaurants to choose from and such. Both have impressive stats, but I think JH has an edge as far actual skiing goes. You can ski the entire vertical using the JH tram, whereas it takes two chairs just to get to the BS tram. Less people at BS, though... Make time for a trip into Yellowstone or riding snowmobiles on a non-skiing day, you can do it from either.
If you are feeling adventurous, fly into Bozeman, rent a SUV, and drive to the smaller ski areas around MT while staying at motels and eating at local bar/restaurants. Not glamorous, but fun! Bozeman and Missoula are both great towns. Just google the ski Montana website for more info.
Good luck and have fun!”