Subs unless voice actiog is good. unlike Evagelion, I CANNOT stand the voices.... and sometimes it makes it feel like my ears are bleeding from the voices....
I prefer subs more often than not because dubs usually dont capture the emotion of the characters. Ive heard horrible dubs that felt like the voices were merely reading a manuscript, ugh.
Both~
Subs: They sound better than the english voice actors, but sometimes the transcripter who wrote the subs has a poor choice in words and sometimes I'm not sure what exactly they're talking about.
Dubs: They usually have sucky voice actors.... but at least they're speaking english and I don't have to pay attention to any subtitles and instead I get to pay full attention to the whole scene.
Dubs are also really bad, sometimes, because of mediocre translation, censorship and much of the language being lost in translation as well.
For an old school anime I think Berserk was dubbed well though.
I sometimes like to game and watch so dubs help a bit. Dubs are generally shows that I wouldn't take the time to watch or have already finished subbed. Hentai on the other hand are 100% subbed.
Pertaining to hentai, I cannot tolerate the dubs, it just ruins the unique Japanese erotic aesthetic for me. Anime in general, some dubs I am quite fond of. It all depends on the voice actors, really.