As far as American vs Japanese goes, there really is no black and white comparison as it depends on the guitar and Japan puts out guitars that blow away a lot of American guitars. Like ESP Eclipse 1 CTM full thickness' for example (not available in north America), they are a far superior guitar than a Gibson les paul custom IMO.
ESP makes a lot of very high end guitars and its irrelevant that they are a Japanese company.
I find Japanese guitars more consistent (flawless in every way) as the Japanese (generalization) have a different mentality than westerners and have a very strong work ethic, it dates back to the Samurai and is still very evident in todays society. I have never known any worker with more respect and pride than a Japanese individual.
