We booked the Discover Tortola tour through our cruise ship, and the tour was operated by Elroy's Pleasure Tours. The meeting time was 12:50pm, and the tour time was 1:00pm, and we were booked for a 3.5 hour tour, with all-aboard at 4:30. Cuts it close, but OK. As of 1pm, there were still no buses available as we waited outside in the short downpour. It was well past 1:15 by the time we actually got on a bus, and we were by far not at the end of the line. I was back on the ship by 4, so the tour was nowhere near 3.5 hours.
The driver was Ishmael, and he was knowledgeable about the island's history and culture, and very patient with some of the out-of-left-field questions being asked by other guests. We had several people who had limited mobility on the tour, so I believe Ishmael made a couple of executive decisions to not let us off the bus in a few places, instead just pausing at the side of the road so we could take pictures from the windows.
We drove around the island and had a stop of about an hour at Cane Garden Bay Beach. I was pleased with the content of the tour, just not with waiting over 30 minutes for the tour to start. I would do a similar tour, but not with this operator.