I usually like subbed, though some dubs are pretty good. Usually when it's a movie or something released in theaters, the dubs are pretty good quality, but I find dubs for TV shows kinda annoying. I can't quite place my finger on it, but sometimes it just doesn't sound right. I think the reason I like the original tracks more is probably because I can't understand them that well. Are they acting well? I dunno, but it seems like it! In English I can tell when someone is overacting or underacting or sounding like a complete moron. In Japanese, it's a lot harder since I'm not fluent with the language.
Another reason I like the original tracks more is because the annoyingly high pitched 'cute girl' voice actually sounds really stupid in English, but I like it in Japanese. This probably goes along with the 'I don't understand what they're saying' thing.
I also like those wierd sounds that animals make while they talk (ex: the puchigusos go: 'puchi!' or something at the end of the sentences). They sound kinda cute in Japanese, but most of the time there's no real translation into English for these things.