Always have Japanese with subs on if it's available, I can't stand english dubs of Japanese products. Perhaps the dialogue is as corny and over-pronounced in the original language as it is in English, but it's way less noticeable to me if it is.
On saying that, it grates on me when people say that just because I can't speak Japanese that I can't get a good grasp of how well someone's voice acting is. Knowing what's being said by reading the subtitles usually gives me a good idea of how the lines are supposed to be delivered. Hell, after watching the second season of Toaru Majutsu no Index I thought about how well-performed the character of Accelerator was, a bit later finding out the voice actor won an award for his role.
On saying that, it grates on me when people say that just because I can't speak Japanese that I can't get a good grasp of how well someone's voice acting is. Knowing what's being said by reading the subtitles usually gives me a good idea of how the lines are supposed to be delivered. Hell, after watching the second season of Toaru Majutsu no Index I thought about how well-performed the character of Accelerator was, a bit later finding out the voice actor won an award for his role.