We did the half-day circle the island tour with Marama Tours.
It's great that you can see everything you need to see in about 4 hours, that leaves the rest of your time in Tahiti for relaxing or other excursions. Our guide Jean-Baptiste was VERY knowledgeable and friendly. He spoke fluent English.
We booked our tour ahead of time online. I liked that they took credit card as most places only took local cash. They were very quick to respond via email to any questions.
Would reccomend this excursion.