After his appearances in the Big Finish audios, Geoffrey Beevers has become my second favourite portrayal of the Master. The mantle of my favourite Master has to go to the definitive Roger Delgado; a very hard act to follow. Whilst in the third place, I have to give to Alex Macqueen, despite his one (soon two) appearance(s) in the audios.
I agree that Delgado'll always be the best and Beevers is really, really good. That dude's voice is chilling. Early on when I first discovered Big Finish, I walked into Dust Breeding having no idea about the big twist- quite a shock. I like how they're continually weaving him into Tom Baker's BF stuff- nicely pays off the end of The Deadly Assassin, which promised a revived Doctor/ Master feud, but never delivered (gotta wonder what would've happened if Hinchcliffe hadn't been forced to leave).
I like all the Masters (even Roberts). Ainley gets an unfair amount of criticism- probably some sort of "fanthink" that started in the 80s and just rolled onward from there. Yeah, he gets pretty "arch" in some stories, but I think that had more to do with individual directors (and even when he's hamming it up, he's fun to watch). At the very least, his performances in Logopolis and Survival are deadly serious and really damned good.
He must be inside the Melkur TARDIS...Given the lighting, and that version of the grandfather clock TARDIS is from "Keeper of Traken"...The Grandfather clock TARDIS from "The Deadly Assassin" is an older design.