I've never used a BB, but I'm all for glass:
I don't worry about scratching glass,
It's easy to get clean, and remove odors (ale pales are PITA to remove odors, not sure about BB's),
I don't like my carboy to flex when lifted (full),
I don't worry about what's in glass, because it can ALWAYS be cleaned,
It will last 10 lifetimes if taken care of,
It won't break down, or cloud if left in the sun,
It looks more professional/sanitary,
And I don't like plastics. I will by food products in a glass jar, over plastic every time. There's too many articles about all the chemicals that can be imparted into food from plastic containers.