Meh, if it weren't for Rod Cameron, Ghidra would be the John Wayne of spaghetti westerns; a stoic, average, actor who is somewhat effective.
As far as The Ultimate Killer is concerned: A film that is predictable, full of cliches, that has hardly any kinetic energy. Vari's directing is nothing to write home about. Its best aspects are the performances of both Ghidra and Eastman, and Pregadio's score.
Day of Anger is, in my opinion, way better in every aspect. Van Cleef and Gemma blow Ghidra and Eastman off the screen.