Lots of runs, big mountain feel, decent lifts, can have decent snow
icy, snowblowers in your face at the top of a crowded mt., crazy skiers/boarders
We have been to Killington in December and early March. There was a huge difference in the snow quality. December was icy and some of the steeper runs bordered on dangerous unless you slowed down considerably. There were tons and tons of people on the mountain so you had to have eyes in the back of your head. Many of them could not ski or board safely in a crowd. The runs are still great, some long and some with considerable variety and challenge. The mountain is not laid out well though so you spend a lot of time traversing instead of skiing. March was better as the base of snow/snow fall made for less icy conditions and the mountain was not nearly as crowded. If you go, go later in the season as the cold won't kill you either. One day it was 5 at the top before the windchill.
The prices for lift tickets, local lodging and food are high for the east coast. I feel you are better off taking some quick runs at your local ski hill and then going out West for a week long vacation. The price of tickets, lodging and food is about the same and the skiing is worlds better.