Regarding barre chords, I'm finding that for the nylon string and classical stuff that requires barring, my left hand quickly fatigues - especially at the flexor muscles in the wrist that go up to the forearm (for you anatomy buffs out there), e.g. feel lots of strain on the palm-side of the wrist. Not sure if my guitar for some reason is harder to play (action is fair, not high) - though how could my guitars be any harder to barre than anyone elses, given the same action height and length of strings ?