Gintama in general. Sometimes the translation's good, and they have fun with the parts that just flat don't work in English, others it's very very textbook and stiff. Sometimes there's honorifics, sometimes there isn't, sometimes all of the swearing is intact, sometimes it isn't - stuff like that.
If you want an interesting contrast, watch the first few episodes of the anime, then skip ahead to a recent episode. Viz translated the first fifty-some odd episodes of the anime, but someone else is translating it now.