I have used Lisp languages far more often than Prolog, but I do have my own Prolog success story: I had just used ExperLisp on the Macintosh to write a little app ExperOPS5 for the company who wrote and marketed ExperLisp and ExperProlog. After this I was given an internal research grant to write a complete simulation environment in ExperLisp as part of trying to win a large contract. Given familiarity with the tools I was using, a good prototype took about 100 hours to write. I had time left over and talked with my management about doing a parallel implementation in ExperProlog. Using a declarative approach, I had a parallel system, with interactive UI and graphics done in about 40 hours - and I had a learning curve with ExperProlog.
I have also used SwiProlog and occasionally Amzi Prolog also since then. SwiProlog’s semantic Web library was the basis for all my early work and experience with semantic Web and linked data. I definitely suggest trying Prolog on a few small projects and add it to your tool set.
Have you been feeling dire expressing your code while having only (Subject, Predicate, Object) first order logic? What kind of requests your app could manage and how large was DB (how many triplets)?
I have also used SwiProlog and occasionally Amzi Prolog also since then. SwiProlog’s semantic Web library was the basis for all my early work and experience with semantic Web and linked data. I definitely suggest trying Prolog on a few small projects and add it to your tool set.