Mig-29 is a scary little plane in the way of manueverability and durability, especially in the hands of a competent pilot.
If the pilots themselves are both of equal skill, simply engaged in dogfight, then I'd have to say the Mig-29.
Otherwise, definately the F/A-18.
...and in a dogfight versus the Su-27 series, forget it. Them's is scary.