I went a couple weeks ago. It was an absolute blast. There are 3 different groups to choose from depending on your ability level and powder skiing experience. They will pick you up from your lodgings and transport the group to Buffalo Pass where you board the powder cat and go. You get on the mountain before 9:00. At mid-day they take you to their cabin where they serve you a nice lunch. And then you ski for the rest of the day. They also provide the skis & poles (and breakfast & apres beers)
2 Guides ski with you (1 drives the cat) and are there to help dig you out if necessary.
If you are a level 8+ skier, likes to ski trees and have some powder experience then I recommend going with the advanced group. We went with the intermediate (lowest level) group because we were afraid my wife would slow down the advanced group, but she wasn't even close to the worst skier. We got slowed down a little, but not really too bad except for the British guy who got lost for a 1/2 hour. A couple of people pretty much just rode in the cat.
All the lines we skied were fresh (really deep) powder and we got to ski some trees (aspen & pine), and long meadows.
I will be doing it again, but with the advanced group.
Check out the videos on their website and you will get an idea of the types of terrain.