Asta1227,
I spend a great deal of time in Tahiti, but have not been on the Aggressor. Have heard positive comments and read pretty good reviews though. Remember that Tahiti is not known for soft corals, go to Fiji for that. Most people go to Tahiti for pelagics. Lots of shark....mostly black tip, lemon, reef, but you can find hammerheads as well. Mantas and turtles are good here as well, and the majority of the dives will be drift through the pass, and around the corner of the pass. But don't expect to be impressed by the reef itself.
The liveaboard is an out on SAT, return on FRI from Rangiroa. Best bet is to spend 2 weeks. It's a difficult destination, so one week is not enough to have a great, relaxing vacation, especially if one week is diving on the boat. Plenty of options. Go early or stay later and do the Manihi, Bora, Mo'orea thing. From Bora there is a non stop flight to Rangiroa on certain days of the week, and also a flt from Rangiroa to Manihi, so you can plan your itinerary around the Air Tahiti flt schedules. They have a link, so do a google and take a look at their flt schedules and check out the multiple island passes, which will save a few bucks. And Tahiti is expensive, so saving anything is a good thing.
There are also plenty of shore based dive operations on Bora, Rangi, Mo'orea, and others as well, so you can also get some nice dives in after the Aggressor.
My suggestion is to try and get there in the first half of July. There is a big festival, celebrating Bastille Day (French polynesia), and the islands of Tahiti, Bora, are great for this. Traditional dance competitions, and a lot going on during the day with various demonstrations, and partying in general. Highly recommend this as many don't get to see it. Worth the dancing alone. Do another search for "Heiva". I would provide links, but not possible at the moment.
hope that helps
