Room Selection Sandals Grande St. Lucian

I am looking at the resort to go on my Honeymoon next year, and I was wondering if there was major differences between the rooms other than services offered, and if the upgraded rooms were worth it? My main concern is with the room service being offered only in some rooms. The upgrade to a room with room service could be anywhere from 1.5k-750. Any other feedback about the resort is also welcome, thank you!