Asking what makes a tobacco good is like asking what makes rock music good. It all comes down to a matter of personal preference. Quality leaf and quality flavorings could be used on a blend but there will still be some people that just do not care for a blend. For instance, Boswell tobaccos use top quality leaf and have top flavorings applied, but there are going to be some people out there who just don't care for aromatics. Likewise, Sam Gawiths FVF is also made of the highest quality tobaccos, but for people like me who don't like smoking straight VA, it's just not a smoke that would appeal to them. There are some people out there who probably smoke nothing but Borkum Riff because they enjoy the taste of it, and there are some people who only smoke the highest quality English blends. I guess what it all boils down to is that to your taste buds, a "good" tobacco is one that you enjoy the flavor and doesn't cause tongue bite, because at the end of the day, that's really all that matters.