The scene with Toby Esterhase and George Smiley in the basement office of Toby's gallery is one of my favorite scenes on film of all time.
Alec Guinness was a master at not overplaying a role
Definitely. I think it is even better than "Tinker Tailor Soldier Spy" (also with Alec Guinness). The execution, the acting, the plot, the screenplay, everything is just marvelous.
I watch it in part or whole, monthly (sometimes I swap it for the film, or for Smileys People...once I swapped it for The Night Manager, but that wasn't as comforting).