I prefer subs.
Before the cries of "Weeaboo!" start, I actually prefer subtitles for anything that was originally in another language. If I'm gonna watch a german opera, I'm going to want to hear it at least once in german. Hearing it in it's native language just tends to give you a better experience, because that's what it was originally written for and that's what the writer had in mind.
I have heard decent dubs before, though, and a rare few that I thought were very good. I just tend to prefer the japanese "over-dramatization and emotionalization" over the performance typically given in the dubs by the english VAs. I like that in general as well, so it's not just in anime.
Disclaimer: This is all my personal opinion.