As they say, your milage may vary - but here's mine:
Overall Average = 15.5mpg
All interstate yields no more than 18.5mpg - usually 17mpg while cruising at 75-80mph
All city will yield 14 or less. Has been as low as 11mpg when I first got the VX and was overly frisky with the loud pedal. Two speeding tickets and hundreds of dollars in lawyer fees within the first month of ownership (after having a clean record for years) seemed to increase the in-town mileage somwhat.
Apparently city mileage could be better though. Just yesterday my girfriend said "My GOD! Why do you ALWAYS drive like a bat out hell when you get in this thing?!? She's got no room to talk though. Every time we swap vehicles she says she's got to get her Xterra back before she gets her license revoked. There's just something about a zippy little VX that makes you want to hammer it even though you know the groceries are going to be all over the place when you get home...