^ i agree to this U_U
I've once compared (with my 'more or less' knowledge on japanese writings) three to four of RAW pages with a few free-translators + Viz's work. Since Viz is an official translator, it has the least mistake in such task and tend to translate most epithet into English too, while MS rephrase dialogues a lot so some of them are either good or bad highlight to the image and situation, MP is... like taking dictionary form at some points, especially when it involves Kanji character and dialect.
Also, a few manga translating comparisons were already made by more knowledgeable people out there.
PS: But i'm not sure if there's any member among them translation teams have been changed or something, recently.