I've watched the entire SUB series of Index and Railgun and all the little extras and OVAs. The dub is decent, not perfect, but decent. I can live with the "bug-zapper" and other terms they've decided to use. BUT "SISSY" is f*ing retarded!! Why can't they just use Onee-sama? It really is difficult to translate the meaning of titles and honorifics. Even "sis" or "sister" would be better. "Sissy" sounds so degrading. Onee-sama is a term of respect. If I were to translate "sissy" into Japanese it would be "nee-chan".
Kuroko is my favorite character and her English voice is decent, but I cringe each and every time she says that horrible "sissy" word.