I'm in the market for a new car (new to me) as my faithful old Vectra is coming to an end. I'm looking at getting an Insignia and after thinking about it a bit also a Mondeo. I've only ever owned petrol cars but there seems to be a lot more diesels around. I've been put off diesels a bit from friends who say they are dearer to run in the long run and the government seem to have a vendetta against them. The Mondeo's seem to be better spec'd but I'm struggling to find and petrol versions, I thought auto trader etc would be full of them but not so, there is plenty of Insignias though. So what is best to go for Petrol or diesel and Mondeo vs Insignia. Looking at around a 2010 model.