Ronald Held wrote:
MI and The Avengers were good but not in the same class as TOS.
M:I was at least AS good as TOS, and I would say the best M:I episodes were better than the worst TOS episodes.
At its best (i.e. the Emma Peel years), I'd put THE AVENGERS up there with TOS. It had a unique charm and oddness about it (which the Uma Thurman movie tried and failed to capture).
My memories of M:I are pretty fuzzy at this point, but I remember liking it as a kid. Alas, I probably haven't seen an episode since its original run so I can't rate it with any sort of confidence.