Pros : I've never had problems with Bullseye glass, black or otherwise. Great consistency of color, predictable firing results make for enjoyable work.
Cons : None.
Other Thoughts : I've found that as long as the cutting wheel is perpendicular on the smoother side of the glass, (as most instructions for any type of glass recommend) and most importantly, well-oiled, cutting and breaking is predictable, certainly no more trouble than other glasses. Bullseye has excellent reference material available online to get the most out of their products without the headache.