I drove the 1.6 ecobooston test and I have to say it's one of the nicest petrol engined cars I have ever driven. It was very torquey and I actually managed not to stall it. which, after some 14 years of diesel ownership is a minor miracle and says a lot for the engine. However, I didn't find it any quicker than my 2.0 TDCi which is averaging about 45 MPG in my hands. Diesel is now £1.54 a litre here in Shetland, and for some obscure reason, Petrol is now 12 pence a litre cheaper, at £1.42. However, given the figures, and the fact that the Tax on the Diesel is less, the diesel is still the cheapest to run. I can't speak for a naturally aspirated petrol engine except to say that the last one I drove was gutless and noisy! Almost exactly what they used to say about Diesels!
2008 2.0 TDCi Zetec