We stayed at the Sofitel Private Island for 9 nights as part of our honeymoon in bungalow 130. Overall it was an excellent trip and the hotel was a fantastic part of our experience. Greeted with an ice cold coconut to drink, and a bottle of champagne on ice in our hotel room waiting for us we really were very happy.
I had reviewed the various tripadvisor reviews at length to pick this hotel and there are a couple of things to note if you're doing similarly and comparing this hotel vs others:
You get free Wifi on the island (though its a bit patchy in places)
You get a free mini bar in your room that is refilled daily
If you're staying at the other hotel you have to pay $10 a day for a shuttle that takes you over to the private island
Some of the better snorkeling is on the northern point of the private island
These little features and a few others really made this feel like a top notch hotel. I thought the room was very well equipped and generally the island had everything we could ask for in terms of features, though I will say when it rains you can get bored quickly!
You should be aware that food is quite pricey, but thats Bora Bora for you. Personally I'd have liked something with a few more stronger salad options but thats just personal taste. The one thing that did annoy us was the trips that were booked, the shuttle is always late and in one instance for us the shuttle didn't arrive at all and we didnt get to go out to dinner that night! There is a very relaxed atmosphere when it comes to punctuality!
The hotel (and I believe all the hotels) have a deal with a restaurant called Bloody Mary's, some friends we made advised us against going but the concierge insisted so we went. Bloody Mary's is equivalent to TGI Fridays, its terrible, absolutely awful. Horrible food, service and rude shuttle drivers. Dont waste your time!
The one thing I would say, and this is not a mark against the hotel is that my expectations coming into this trip were matched with our trip to the Maldives last year and the snorkeling in the Maldives is 100x better than in Bora Bora. There's still some nice snorkeling to be had in Bora Bora however the Coral Reefs here were almost all wiped out due to a cyclone ten years ago.
All in all an excellent hotel that we would go back to again!