Tom Baker sucks and is overrated. [/controversial opinion]
Overrated? Possibly. Sucks? Oh, I wouldn't say
that.
Patrick Troughton is the definitive model. ;) The ONLY person who could have followed Hartnell's great performance.
I just watched
Tomb Of The Cybermen again, about a week ago. Classic stuff. I certainly wish more of his work was left to be seen.