I was really interested in seeing this just on the basis of the actors, and also because I've seen it twice onstage, once with a TV-oriented cast (Jonathan Frid, Gary Sandy, Jean Stapleton, Marion Ross, Larry Storch). This 1969 version has its moments, and Bob Crane and Fred Gwynne are both noteworthy and hold up their end of the bargain, but it's still more or less lukewarm as a production. I see that there's yet another TV version with Tony Randall as Mortimer and Boris Karloff(!) as Jonathan... I'd love to get my hands on that one, if only to compare it against the other versions. In short, this 1969 version is a curiosity and mildly entertaining, but nothing to toast with a glass of elderberry wine.
Review of Arsenic and Old Lace
