I dont think it is necessarily good or bad. I think its more about the sense you got from your interviewer. For example, if your interview goes over time and you feel as though its because your interviewer has not got the answers to all his questions yet then perhaps thats not a good thing, but maybe your interviewer was just interested in your responses and the conversation taking place. In my interview, we ran over by a bit and my interview was mindful of the time but seemed to continue to want to talk to me for a little longer. He answered my questions to him very thoughtfully and with a detailed response so he wasnt trying to rush me out of there. Also when he asked me about his research after giving a brief response I asked if he wanted to hear more about it and he did so he seemed genuinely interested to have invited me to speak more in depth about what I do. I wouldnt worry about time, just think more about how you felt during and after the interview. Also some interviewers can seem very withdrawn and stoic but that doesnt mean you did bad. Ultimately I would say reflect on the feeling you got from the interview but dont stress about it wondering what this meant or that meant or if it would have been better to say this or not say that because you NEVER know exactly what the interviewer was looking for and the impression they received so just relax, try and enjoy the time between now and decision time and freak out later when you get a decision