i went to Vail and Copper Mt. back in 2009.
i liked Copper better for a few reasons, the way the mountains terrain is naturally it keeps people that are new to snow sports to one side of the place...the terrain from right to left goes from (easy to intermediate to more advanced...) which is great because you don't have people falling in front of you all of the time or camping out on the slope. another thing that copper has FREE parking and they have buses that drive you to the gate. that was one thing i hated about VAIL, they nickel and dime you to death...don't get me wrong Vail is unbelievable but they know it and they are going to charge you for it. Copper seamed more like a laid back place.
Look into the "Copper Mt. 4 pack".
They offer a deal were you can get 4 tickets to be used how ever you wish...(4 days for one person, 2 days for 2 people, 1 day for 4 people, how ever you want to use the 4 tickets, ect) i think you have to buy them before a certain date tho. i have been wanting to buy this package for a long time but all of my friends are gay and will never commit to the trip, and CO is not the type place you go to snowboard without making the best of it. hope this helps.
Wesley