It was a no-brainer for me; my company has a strict diesels-only carplan.
I did drive both of them though, and I must say that I personally like the diesel more. It's just quieter, easier to drive and more economical (diesel is 20 cts/liter cheaper over here) I don't really care about the economical bit, because my boss pays the bill, but I do really like being able to drive 800km + on a tank full.
Sure you might be able to get around corners a bit faster in a petrol if you drive it "just right" but I don't want to do that, I just want a car that is fast to overtake and quiet on the motorway and that would be the diesel Civic
