I own a Hybrid
There's not much point in comparing laboratory or government figures. Go to one of the 'MPG' sites, such as www.fuelly.com. There you'll find real figures for everyday driving. The distributions of actual mpgs are a very good indication of what's generally achievable. BMWs and Hybrids return different figures because the drivers are different: not because it does "4.5 mpg more than a 3 series"
My Prius does about 59 uk mpg (measured lifetime value over 10k miles). Today, a hybrid is needed to give a good range (say 500 miles) to a tank, reliably. Sure, there are diesels that will do better. They tend to be smaller, and manual. Mine's 1800cc petrol + an electric motor, in a 'medium' car and fully automatic. It cost quite a lot more than a smaller diesel. But the engineering is very focussed on achieving these emission/mileage figures. Some of these compromises I don't like, but overall it seems an exceptionally cheap car to run.
Nearly 60 mpg, tyres have little wear, the brakes are hardly touched (it uses regenerative braking), the engine compartment is clean as a whistle, and..no tax. It gets an oil change and filter for servicing. That's it.
A car built for mileage teases you into optimising your mileage. It changes your driving style. Out go the high speed drives in a powerful car. OK, it MAY be a bit 'boring', but a quiet car and a good sound system compensate....
Biting the hand that feeds IT
