I think Killington sucks ass. You'll find most people love it or hate it. If you're looking for nightlife and partying more than riding, it's the place to be. But the mountain itself is not all the hype it up to. It is huge, but only in acreage. It's not all that much in the way of vertical. Lots and lots of very short intersecting trails spread across six "mountains," which are really just peaks along the same ridge. And the layout is horrible. If you miss a turn, you can easily wind up at a whole different base lodge and it will take you an hour to re-connect with your friends. The various base lodges work their slightly uphill with long traverses...meaning, if you end up at the base area farthest to the left, it's all uphill to the base areas to the right. Sucks on a snowboard.
Plus, they lie worse than any mountain I've ever seen. It's not uncommon for Killy to be touting 6" of fresh pow when every other mountain nearby says freezing rain or wet snow...they just want to get the New Yorkers up there, knowing they're stuck once they arrive.
All that said, I'll probably ride there a few times this year, since the Ski Council has several Killington days on it's calendar for about $40. I'll ride just about anywhere for a $40 lift ticket. Even Killington.
You might want to look into it depending up when you're going. You can get 3-day lift ticket through the Ski Council for $98. It's normally at least $84 for a one-day ticket. Deal of the century!
Its def still up in the air. I had a good time at Stowe and I don't need a huge nightlife because I'm there to ride..