The tour was great, we got time inside the Sri Shakti Temple (I was only expecting a photo stop), visit Melawati Hill and see the views and monkeys, buy our own dinner (because we didn't like the set seafood dinner tours), boat ride and fireflies.
As with all things nature, its a bit of luck on whether you interact with monkeys and see fireflies. The success for our tour really comes down our driver and guide LG. It was raining in KL, it was a Saturday, traffic was bad meaning timing was tight, but we still got to through the itinerary, we didn't feel rushed, LG gave just the right amount of commentary, got us up Melawati Hill, and liaised with the boat company to get us sorted on the busy jetty. A very safe pair of hands.
Re: the fireflies, there is a number of reviews that question whether its worth the tour. IMHO, sure they are like low wattage xmas lights, I'd recommend doing it if you haven't seen them before and because its an experience in a new country on top of the temple, hill, monkeys, commentary and boat ride.