It very much varies on a show-to-show basis for me. Although as a very general rule with lots of exceptions I find that the newer the anime is the better the dubbing is; apparently because they're actually starting to get decent voice actors to do it. And the reverse is true for subtitles, presumably because older anime had to be manually translated whilst these days the script can be fed through translation software and just stuck in.
I found the subs for Madoka Magica to be particularly bad, for example. Fortunately I found the dubbing in that to be pretty decent. On the flip side I've been playing Hyperdimension Neptunia Rebirth 1 (admittedly not an anime, but its an anime-style game) recently and the English voice acting for it almost made my ears bleed. So it varies a lot.
Although I have to say that given I've been watching a lot on crunchyroll lately I've gotten very used to subs on everything.
I found the subs for Madoka Magica to be particularly bad, for example. Fortunately I found the dubbing in that to be pretty decent. On the flip side I've been playing Hyperdimension Neptunia Rebirth 1 (admittedly not an anime, but its an anime-style game) recently and the English voice acting for it almost made my ears bleed. So it varies a lot.
Although I have to say that given I've been watching a lot on crunchyroll lately I've gotten very used to subs on everything.