Matter of taste. I prefer it in japanese, you prefer dubs. Japanese VAs, however, do have a higher quality on their acting than American, generally speaking. Some dubs can be fine, and some can be excellent.
It's like Swedish Disney dubs - they're generally very good, since Disney gets actual actors to do the voice acting - and actors, as we all know, usually know how to act. Q.E.D - the dubs are pretty good.
American VAs don't do this whole repertoire of singing and training their voice stuff that Japanese (or, indeed, German) VAs do, and as a result, they're generally a lot worse. Basically, voice acting in America isn't a profession, it's a hobby.
It's bound to change in, say, 10 years or something like that. But for now, they're just not professional enough.
Pronunciation is a big thing too - American VAs can't pronounce japanese names or words, this is a fact. "Mahn-ga" and "annie may" is not how it's supposed to be, and shit makes me rage harder than the badly done acting.