Actually, it may just be the Alvarez. I recently upgraded from a small-bodied (RF-20) Alvarez to a small-bodied Martin (000-15S), and it's like the world opened up. Leaving aside the tonal differences between the two instruments, the subtle differences in the shape of the neck and the action make an incredible difference. I was never able to master thumb over bass notes or barre chords on the Alvarez and an hour's playing left my fingers blistered under the calluses. Now I can do the barres and thumb overs, and I just spent 8 hours at a jam on Saturday playing the Martin, and my fingers are fine. No dents, no soreness, just a tired happy camper.