[egroat]

I find twice to be relatively outrageous, but both my mother and I having the same car (Toyota Yaris) from the same year with mine being a diesel and hers petrol the following is noticeable:

* I get about 1.25x the mpg in the diesel to her in the petrol. 1.5x compared to myself in the petrol (no mpg quotes because it depends on the type of driving)

* The torque is useful. I drive a 30 minute commute, mainly motorway. If I drive hers it is a noticably worse drive.

* For in town driving hers feels better every time. Easier to handle with no load (hauling something? Use the diesel), the diesel tricks me into speeding.

* Wet weather? Never had weather problems in either car.

So whilst I am definitely a less efficient driver than her I save a significant amount on fuel by having a diesel, and my calculation shows its several hundred a year better than if I had bought the petrol when I had the chance - more than covering the increased cost of the initial purchase.