My wife and I hopped on a local tour of St Augustine, hoping to get a good overview of the historic area, its architecture, and help plan our walking tour. The tour covered the territory completely. Over and over again. Many loops up and down adjacent streets in an overlapping pattern with the most interesting part the views of Flagler's architectural additions. There are plenty of places to hop on and off, so that feature is very convenient. But much of the tour aspect seemed like filler to me. How to make a short trip into a long one, and justify $25+/person for it.
We added on a side tour that included the Old Jail, the Country Store and a small "museum". The Jail tour was excellent. I'd definitely find a way to see it. The Country Store was a pleasantly interesting 20 min addition. The "museum" was poor quality, more "filler".
Knowing what I now know, I'd buy a ticket for the jail and do a walking tour on my own.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.