As other reviews note, logic isn't a major part of many of this series' scripts, and some of them didn't age well. But keep in mind this was close to a half-century ago, and TV audiences were used to these kinds of plots and writing. (Some of the cars are very cool to see, but the clothing styles are straight out of Barnum and Bailey-guys in every pastel color under the sun, and women wearing huge stiff wigs and dressed in what looked to be upholstery.)
St. James went on to a solid tv career, and Hudson was a better actor than some may remember. Despite the plot and dialogue implausibility they sometimes had to deal with, their characters played well off each other, and that's largely what kept us coming back for several seasons. For many of us teen guys, Susan had enough drawing power to do that by herself--cute, spunky, funny, and just the right amount of kooky. However, I could never figure out why the city brass didn't make Mac--who, after all, was the Police Commissioner--work out of his office instead of running around getting into gunfights.
The series isn't the top of the TV-detective heap, but it represents the era....a comfortable and friendly revisit to a more innocent time.