I agree it's personal preference. I like using the stock barrels. I own both old school stainless barrels (.689) and a newer insert style barrel (two piece titanium). both work well for me. With the newer insert style barrels I don't have to worry about rollouts.
I also have a newer one piece 14 inch barrel, but I haven't used it on my buzzard. I would try an aftermarket barrel but I have none that are beveled at the moment. If you do get an aftermarket barrel for your buzzard don't forget to bevel it.