It's a seat. 300 bucks for 5 hours. United frequent flyers (read: high yielding business travelers) will stay due to the massive number of greater opportunities to upgrade, drink, and eat for free, sit in the departure lounges, and fly anywhere in the world using their free miles.
By the way, how's Virgin Atlantic doing, financially?
I wouldn't know, because Virgin Atlantic is a separate entity from Virgin America. I did hear however that Delta purchased a 49% share in Virgin Atlantic (share from Singapore airlines).