I’ve stayed at Saii and Conrad although not in OW. I strongly recommend against Saii. Their sky villas are in large motel-like buildings. Many of their restaurants are a bit of a hike from the rooms. Get a map of the Saii and you’ll see they are a
round Gateway Marina.

I loved Conrad. I stayed at a Beach Villa which had a great beach on a lovely, calm lagoon. There are also other room categories including OW which are closer to the snorkeling beach which was nowhere near as calm and nice.

just my 2cents.