The all vertical Marine aviation was driven by the previous Commandant of the Marine Corps, he even had a vision to replace the -130J with a higher perfromance four engine tilt rotor.
Part of this was the roles and missions fight between the services and how badly NAVAIR screwed procurement. Witness the A-12 fiasco, what became of -18E/F, etc.
With all of the USAF bashing I, and lots of others, do they are the best of the U.S. services on procurement.
Without taking an official poll I would be willing to bet that most Marine aviators are not in favor of strictly vertical fixed wing aviation.
That said, either JSF should be an improvement on Harrier in most areas.
To parphrase Murphy, "If it's ugly and it works it ain't ugly!".