Everything about this just screams "well written". This is like The Godfather of manga in terms of writing quality so far.
I really enjoy the dynamic of Gut's and Casca, especially with how pissed off Gut's got when Casca called him a mad dog. What set him off, though, was the comment about him not changing. Griffith saying that "that trait is, too, a part of my plans" was fantastic as well.