I thought that I recalled that I liked Mannix when I watched it in my teens, but my wife and I caught some episodes a few nights ago and it struck me that Mannix is quite dated. Maybe for its time, it was groundbreaking or whatever but that cachet has vanished. Aside from the great theme music and the charismatic masculine leading man who smoked too much, the acting is often wooden as if unrehearsed or like the director simply didn't care that much. The similarities of the writing to Mission Impossible are obvious --both Bruce Geller productions. The much ballyhooed violence which was an attraction to viewers back then, looks pretty darn tame today. One repetitive theme that we chuckled about was that so many episodes featured someone being killed by falling from a height (with the accompanying scream); usually a high rise or a cliff. In one episode a guy who had been shot fell back out of a fully open window. How many people living 5 floors up keep their windows fully open?? It was a formula I guess, to inject something exciting and violent. Oh one more thing...Compared to Columbo? Forget it.
