Same for me. The first act is heaven but the second act falls flat. I am not a purist, but I really disliked the musical arrangements. The "prologue" is totally unnecessary and some of the Gilbert/Sullivan jokes were rather amateurish. I also agree that the sound was very poor (center mezzanine) and I know POP rather well or else I do not think I would have understood much of the lyrics. One of my favorite numbers (the paradox) is not as crisp as it should be, for example. However, I felt that the artistic team did not trust the original material enough so they had to apply modern changes but the musical really works when they stick to the original concept. Nobody has mentioned the set and costume design. I thought they were awful. I am not sure what they were going for, but it looks like a third-rate company using a rich donor's money. I thought they were awful. They were going for multicultural cute and ended up with tacky 101 (the "trees" in act 2, yikes; the girl's costumes...yikes!). Such a busy, overstuffed, and ugly production.
But the first act is very good. DHP is a national treasure. I hope his Modern General gets on the TONY broadcast. It is absolutely delightful and for once the choreography does wonders. RK is fine, having fun and I loved Barasch and Preston Truman Boyd. But the rest of the cast is not ideal, unfortunately. I thought that Monsoon was all wrong for Ruth. The choreography was typical ADHD Carlyle (not every number needs to end the same exhausting way). The male dancers were great. The first act is great though. We left at 10;20, but the last 40 minutes felt like a couple of hours.