I have recently returned from FP and I can say that Tahiti is really a 3 day stop the most. At the IC do not waste your money on those overwater bungalows.
Go to Moorea there are many top notch options, be aware the IC there is undergoing redevelopment so the pool was closed and very noisey construction. I stayed at the Pearl Resort and would recommend it.
Due to recent local issues I have noticed many accomodation deals on the internet that include airfares to Bora Bora and Moorea so you can do both if you so wish. Or stay at Moorea, great snorkelling and stunning scenery.^