I don't have any bar recommendations, but I can tell you that buzz in bars results in a large number of fast, involuntary muscle contractions in your forearms. This is what causes arm pump and numbness, tingling, and fatigue. I don't know if arm pump is a concern in distance cycling, but it sure is in motocross racing (where you've got a single-cylinder engine turning the machine into a vibration factory). Different people have different sensitivity to it, but if you feel any buzz, it'll be worth tracking down given the amount of time you'll be spending on that bike.