They are actually very good on fuel around town and you still have the power there when you do put your foot down. A v6 you really do have to wring there neck to get anywhere hence you do use alot more fuel to actually get there. There is a formula around some where for this.
Don't want to sound like a bitch, but a VE V6 uses less fuel then a V8. Otherwise Holden wouldn't be selling them. I get 6-7l/100km from pakenham to melbourne everyday.