Well heres another opinion. I stayed at both the Nui and Sheraton Moorea. First I would say the OWB is 100% worth the splurge at the Nui. Diving off of your deck into 15-20 feet deep of crystal clear water is well, nothing short of amazing. We never wanted to leave our room. Being able to snorkel right off youre own "home" is awesome. Plus the island itself to me is no where near as beautiful as Moorea so by not leaving you aren't missing much.
At The Sheraton Moorea the OWB is probably slightly better, simply for the OWB experience. The OWB's imo at the Sheraton aren't the same feeling one gets at the NUI. At the NUI there is more of a sense of being there alone snorkeling in your own ocean! The Moorea (esp during the day) the way things are set up...snorkelers, and people can be around and near all day long. And.....the beach bungalows are really great. The grounds the way they are landscaped at the Sheraton make it a great setting.
If money or points arent a big deal go for both....However I wouldn't flinch one bit by not getting the OWB in Moorea.
Personally when I go again....I would spend as many points or dollars as it took for the OWB at the NUI. However I would go the cheaper route in Moorea. Snorkeling off the beach in Moorea is way cool so the OWB isn't necessary....and being "out....exploring the island" is the way I want to spend most of my time.