I'd have said that at least historically Fords rust worse than Vauxhalls - case in point: mk3 Fiesta.
Now I'm getting a bit worried, as two seemingly perfectly reasonable people have now referred to the XE engine as a 'red top', something I've previously only heard chavs do. To misquote Phil Mitchell, "Ave a word. Sort it aaat".
I actually have quite a soft spot for the mk3 Cav (no, not the wheelarches

), in the same way that the mk4 Astra is a great car overshadowed by its blue oval rival of the day (arguably due in a large part to the influence of the motoring press, who were most likely slipped more backhanders by the chaps from Dagenham

). GSI2000s were particularly tasty, although I prefered the Carton GSI3000. Having said all of that, when was the last time you saw a Cav SRI or GSI which wasn't being driven like it was stolen?!
cheers
James