The terrain at killington is great. the resort is big and will keep you exploring all day long. the hills are very populated on a weekend. lift lines are okay but the gondola ride fairly long when traveling there on the weekend. hotels get booked quick and hard to get a hotel or motel if you just show up on a road trip. if you travel a couple miles from the mountain there are many hotels and motels that are fairly priced and close to shopping/bars/food/gas.
pros: great terrain, great snow, big mountain feel.
cons: pricey, populated, not enough to do on the resort unless you are driving from place to place but that is difficult if you are going to a bar/restaurants