I don't care what anyone says about what Comey did, I don't think he had any other choice. Keeping it a "secret" that the FBI was re-opening the investigation into Clinton's emails wouldn't have been appropriate either. The public has a right to know but Congress most certainly had a right to know.
Now all these so-called "experts" can weigh in all they like, they're not privy to the information Comey has and they don't have any idea of what has been uncovered. Comey may not even know at this point, in fact, he has said that he doesn't know if anything is significant to the case or not at this point. The fact that he had testified to Congress that he had closed the investigation can't be ignored here. If he hadn't informed them, they would have crucified him if he waited until after the election... that certainly would have looked like partisan political hackery. You may not like to admit that but you have to know that's the truth.