This guitar, when first released, received a 10 out of 10 rating in a ROCK magazine of the time. Martin really thought a superior guitar would really help them break into the world of sellable semi-hollowbody electric guitars. I just read today that the build of these instruments was far superior to one of their competitors, Gretsch, and had considerably less real-estate wood-wise than the Gretsch's...one of the things I've always had cognizance of.
Actually, with the Music Machine and perhaps even Moby Grape using thse, I don't know why they really didn't catch on.
The one I have has great action, better upper-neck playability than the Gretsches....and the firey DeArmond pickups...this could've been one of the great Rock and Blues guitars ever. But, it was not to be.
Very collectable as there are only about a total of 1100 or so of these instruments made.