I have been a travel companion on Delta for 3 years now. If flying internationally it can be a GREAT thing to have. I've flown to Tokyo RT in Biz Class for $400 by using my companion benefits. I've taken about 5 of these trips. You ARE basically flying on a buddy pass but your priority is a bit higher (S2 or S3) than a normal buddy pass (S4). My friend gave me the card because he is single and we travel a lot together. For an employee to sell his companion card he must be NUTS. Not only does he risk the loss of his flight benefits but also termination from the company. My friend is extremely paranoid even with his Buddy Passes. If someone causes a stink on a plane he could possibly lose his flight benefits. So, I would be extremely cautious before forking over 3k. Even with a companion card there is no guarantee of getting a seat. Domestically you will almost always fly in coach but on International flights you have a good chance of sitting in First/Biz.

LS