The lively debate in the US military seems to be, not about whether the F-35’s are worth the money, but why can’t we get these weapons quicker.
I suggest that you study MG Jerry Harris' testimony (linked in my previous post) and the evolution of the Navy's procurement plans in the last three years. After all, in the US military, these are the largest aviation services, the services that have the deep-strike mission, and those principally charged with providing air power to COCOMs.
We all know what the Marines think, but as the man said "where you stand depends on where you sit". Having planned very little in life-extensions or upgrades for Hornets and Harriers, and not having bought a single new fighter in decades, the Marines have a fleet of old and not-very-technically-current airplanes.
Moreover, their airplanes come from the Navy budget. At no point do Marine procurement and operations costs converge in a single Marine top-line where the Commandant and a (theoretical) Marine Corps Secretary have to trade F-35s against amphibs or new barracks or V-22s.
So it's hardly surprising that the Marine leaders want more F-35s, is it?