steeps and glades are nonexistent in the 3 you mentioned...
If you go on the sites , you can find out all the info you need, I have a season pass to Belleayre cause they are pretty close, but then again all 3 mtns are within a 30min drive. Fridays is like $20 lift tickets (I think) at Belleayre, so if you have the choice do that first. I heard that Hunters terrain park is pretty good, heres their blog:
http://ridehunter.blogspot.com/
Windham has a big air bag which Ive been dying to hit, $10 for the day is pretty good:
http://www.windhammountain.com/events-activities/big-air-bag/
Windham also has night skiing...dont know how that is though ($45 for 2-8pm, or $37 from 4-8pm)
Back to Belleayre, its far from a terrain park, with small jibs and 2 jumps that is squeezed onto a run next to the lift, so Id bet on Hunter/Windham for park. Belleayre never really has lift lines though, which is why I like going there..Not crowded at all