I like both but I guess I'll go with orange juice. I prefer the ones with little to no pulp (although it wouldn't be the end of the world if I got one with extra pulp).
I've noticed a lot of apple juice tend to be super sweet so I've been leaning more towards orange.
I favored apple juice for the longest time, but now I'm really starting to feel orange juice. I remember I used argue with a friend about which was a better drink, I guess she was right.