price, hands down cobra.
engine, I prefer cobra just because it comes with one of the stoutest bottome ends ever to leave a factory.
looks, I prefer the vette.
as a package, I prefer the vette because it wieghs around 500lbs less, but I like the driver position better in the mustang.
I'd take either one, but being a poor bastard it's hard to beat a less expencive car and eas of moddablity of the Cobra.