I was quoted £6 cheaper on SeaFrance but I reckon it was worth the bit extra not to travel on a garlic barge, and I prefer to sail under a British flag not a white one.
Sounds like something I'd say at work to my French colleagues!
Seriously though, if I was heading from Blighty to France, I'd avoid Dover-Calais and would still use Dover-Dunkerque, even though it's further west.
Why? The boats and catering are MUCH better on Norfolkline Ferries.