I stayed at Couples Swept Away last year and absolutely LOVED it (I have never been to Sandles, so I cannot comment on that resort). Our room was spacious and like TA Jennifer stated, designed in a minimalist fashion with very comfy beds. The grounds were very well kept and the beach was perfect. The food was fantastic and they even provided a free catamaran that took groups on a sunset trip to a popular cliff diving area known as Rick's Cafe (very fun).
But what was most notable about Couples Swept Away was the warmth of the hotel staff. We were greeted as the taxi pulled up to the hotel with cold lemon-soaked washcloths and champagne. Check-in was hastle free and we only had to identify ourselves once, after that, everyone knew us by name. We were overwhelmed with the hospitality of all the hotel personnel and were surprised when the hotel manager and asst. manager knew us by name and invited us to a special cocktail hour/dinner with them pool-side. We were also excited to find out that the hotel is locally owned (by Jamaicans) and that they support local economies, which is something very important for us, as are policies about same-sex couples.
I highly recommend this hotel and am def planning on returning!!