I don't find there's any difference TBH. If I want a bit of pep I add a little EVOO to the mayo at the end of the process unless I'm making an EVOO-specific mayo like aioli or allioli - the flavour profile of EV olive oil is just too strong for everyday mayo I find.
I agree with that. Its unusual to find any chef who uses olive oil as the main oil in mayonnaise. Mayonnaise uses copious amounts of oil ( hence its copious calories!) whereas a simple vinaigrette uses only a small amount, so the bitter taste a good thing.