Jeff,
If you're shopping at regular markets/big box stores, then no, brand name IMO is not important. There's probably only a few major processors out there anyway supplying the majority of markets. If you want to spend more money for top of the line pork then I'd recommend finding an outlet for Heritage products. Berkshire and Duroc hogs are an excellent product with superior flavor. If this is your first go at butt, then just look for one at your local market that is not 'enhanced'. Enhanced meat has been injected with a salt water solution. A butt doesn't need enhancing and you'll be paying top dollar for cheap salt water.
Paul