The playability issue is, in the majority of cases, due to the fact that Martin so often ships new guitars with the nut slots cut too high. I guess they figure that old bluegrass dudes like them that way ("It can't be a Real Man's Guitar if it doesn't take a lot of strength to play it, and hurts some.") and that everyone else can have them lowered if they don't like it. Most Martins need a setup after you buy them, seems like. And I speak as a Martin lover.

Peter.