Sub. I feel like the voices don't match the characters' personality a lot of the time on dub and the sub actors sound like they take it more seriously (not as cartoony as the dub). Also the talking matching lips (that has always been a pet peeve of mine).
I usually watch it in sub because I will eventually understand what they are saying and that is what I want, but if I'm to lazy to read (yes, it's real. I am that lazy) or am busy doing something I will watch it in dub