I didn't stay at either resort, but have seen both of them and they are beautiful!
Since it will only be the 2 of you, it's all the more reason to go all out! There are several other brides that have only been the ones there. Search for threads by Lilpaisley and JustUsTwo. You can also search for Tensing Pen, Rockhouse, etc. to get specific hotel information.
I think you need to be comfortable in your attire. My dress was formal, and not what most people would think of for a beach wedding. I couldn't imagine getting married in anything different. I tried on a few 'destination' dresses and I didn't feel bridal. I wanted my wedding day to feel specail, not like i was just wearing a white dress.