How much is a VW warranty worth? (on a used vehicle)
 

I'm comparing two used Passats, the one is from a VW dealer and has a VW 2 year/24,000 mile warranty on it (the other's got the generic dealer's warranty of 3 months/3,000 miles) but costs about 2K more.

All other things hypothetically being equal, which is the better buy?

P.S. One of the cars in question is a 2003, the other a 2005, but they have about the same mileage (and have the same features).