Thanks to all for your feedback. I did choose Le Merigot for location (access to the beach) and the existence of a spa (apparently, a spa will be opening at RC Marina del Rey after the first of the year, but RC refers guests to Le Merigot). As many of you suggested, it was a nice property, but very consistent with a FS Marriott property. I was upgraded to a junior suite with balcony; however, I was a little disappointed with the balcony (no chairs, small, high walls), but the service was very good and all of my requests were met. The spa was very lovely and reasonable (thoroughly enjoyed the complimentary eucaplytus steam!). As a Plat, I was given vouchers for breakfast (weekdays only), for $15 each for myself and my guest, which is a little low given the menu prices (no buffet), but the food and service was very good. Parking was a little steep ($35/day), but somehow, I was not charged for each day.
Bottled water provided by the valet was a nice touch. The conceirge was also very helpful in arranging paddleboarding lessons nearby for a fair price, including equipment rental.
Overall, I would stay there again, but not for $350-400/night. If anyone has any questions, I'd be happy to try to answer.