Is it controversial to say that I'm not a fan of any version of the Master other than Delgado? And that's only because I enjoy the dynamic between him, Three, Jo, and the Brig.
Every version since then has felt to me like a generic and annoying comic book villain, with Simm and Dhawan's Joker-inspired versions being the most grating of all. Although I couldn't stand Missy either.
I don't think TPTB have blown the casting of the Doctor yet; each one has managed to prove his or her worth, even when the stories weren't the best. But I think Delgado owns the Master in a way that no one Doctor has owned the part. Gomez had her moments, though.