I think the second option is most important above ALL else.
For example:
I watched Decade, ep. 1 on veoh.com. I don't know WHO translated it, but at times I was left going, "Huh?"
Then I rewatched the tv nihon version of Decade, Ep 1 and it made MUCH more sense. I want to know what's happening in the story and dialogue.
Plus, sometimes fancy lettering/colours make the words harder to read at the fast pace they show up on the screen....sadly TV Nihon has started doing this weird thing, I think its when the rider belt is talking, where colours move back and forth over the words...I hope that made some sort of sense lol.