My wife and I stayed at the Marriott Morningstar Beach which is right next to Frenchman's Reef. We really liked the privacy of being a bit separate from the main hotel and loved that we were right on the beach (I literally could get to the beach within 15 seconds of leaving my room). The room was nice, although a little dated, but being right on the beach more than made up for that. The patios are set up so you can leave your patio window open with just a screen at night to enjoy the night breeze off the ocean.
I can't comment on the rooms at Frenchman's Reef, but we certainly used the restaurants and facilities there. Liked: many restaurant options, beautiful view of the bay, band on the outdoor patio every night, huge iguanas throughout the property, shuttle boat into town (stock up on reasonably priced wine and liquor in town versus the ultra-marked up prices at the hotel for in-room drinks). Didn't like: long downhill walk to the beach (and in reverse, long uphill walk from the beach), overall feel of the main hotel is pretty generic Marriott - not real tropical.
Hope that helps.