I was a teenager when this first came out. My father had to be home to catch every episode and would often enough imitate Columbo's,"just one more thing" schtick.
You can see why there are two pilot episodes. One of them is dreadfully acted by the rest of the cast, while the other is much better. More money must have been available as the series progressed as the small roles were filled with much better actors after the first season.
The quality is, of course, very good and the set includes the made for TV movies, which I haven't seen yet as I am only at season five right now.
Not high energy or fast paced but it is very involving as he agonizingly winnows out the details from the prime suspect. Even my teenage kids enjoy the show very much.