if you can actually find a real butcher (not an easy task in many areas) they should be able to have access to better quality meats.
I find that that is a big deal when it comes to beef cuts, some pork cuts, etc. On things like pork butt, not that much of a big deal, since there isn't really any work I need a butcher to do with it.
Also, a real butcher should be far more knowledgeable about cuts, grades, qualities, etc.
The reason I've been saying "real" butcher is that there are just so few left. Very, very few butchers do any butchering. They mostly get their meats from the same places as anywhere else, and since they don't do much butchering, I find they often aren't much more knowledeable than some of the good meat guys in my supermarket. most butchers today are really more meat distributor than butcher.
I always cling to a nostalgic view that I'm going to find a butcher who is really connected to his meat - where he knows the farms where his meats come from. Where he's custom butchering his cuts. Where he has control over some quality. But, in reality, if I were to walk in the back of his shop, I'd probably see the same cryovac packages from national distributors as my supermarket.
Oh well. Such is the market today. Not necessarily a bad thing, I guess.