This was my introduction to Nero Wolfe, starting a happy 3+ decade relationship with Rex Stout's detective fiction. While this series didn't use the period settings that the later A&E series did, it has my affection for a number of reasons.
First, William Conrad. He is certainly a less gifted actor than Maury Chaikin, but his voice is marvelous, and he uses the declarative, falling cadence that Stout's punctuation indicates. "Archie. I read it because it is a book. And I read books." Chaikin too often uses a rising cadence, which took getting used to, for me.
Second, most, if not all (I am going from memory here) the episodes were, as with the A&E series, adaptations of actual Stout stories and novels, which was also welcome for me as a new reader.
Sure, one could say I like the series because it set the tone of the characters for me, and that likely has a good bit of truth. But I've noticed that, among my acquaintance, the greatest fans of the books are the least enthusiastic about the A&E series, and more tolerant of this series. My husband won't watch the old series when we find it on TV, and doesn't like the books. He loves the A&E series. I also am fond of the A&E series, mostly for the affection with which it was so obviously made, for the period sets, and for the wonderful repertory-ensemble cast, with best acting honors to Kari Marchett, who makes every episode she is in sing.
But see this series for a different and valid take, and the best-voiced Nero Wolfe I know of.