I've been having a lot of issues with the intonation and the tuning of my Gibson 339. I bought it in September of 2010 and since then I have replaced the tuners to Grovers, and I took the guitar to a good luthier that re-carved the original nut in the guitar. He also fixed the intonation. The guitar played great for about two months and now is back where it was before. Don't get me wrong, the problems I mention are very subtle. You start noticing them when you practice your drop 2's all around the neck. Right now I am thinking that if I change the nut and get a new one carved and installed, it might fix the problem. I gig a lot and I hate to take my guitar to the shop and wait two weeks to get it back. My other guitar is a Godin Multiac Jazz which I love, but is not as versatile and the neck can be uncomfortable.