My wife and I were at Pearl for just over a week, and loved every minute of it. We met a lot of fabulous people while there, and had a great time.
We chose Pearl over RM for a few reasons. Being that this was our first "lifestyle" vacation, we wanted to ease into it. Since Pearl's grounds are more spread out than RM's, we figured that would allow us some reprieve if we just wanted some alone time. We also knew that at the end of it, we had to return to our jobs, kids, house, etc.; and didn't want to feel way behind on our sleep.
We kind of laid low the first few days we were there. We both were recovering from minor colds, and were also just enjoying relaxing. By about the 3rd day in though, we started to do more mingling with others, and really got into the swing of things.
We did go to RM one night for dinner and to check out the 'vibe'. I guess we were a little spoiled on the facilities at Pearl, because we thought the pool and jacuzzi (coochi-coochi ) at RM were small and the jacuzzi looked old, worn, and somewhat unclean. In general, as soon as we walked in to RM, I felt claustrophobic. I think RM would be a good place to go for 3 or 4 days if you really want to let loose. And on that note, one idea we're considering for our next trip, is to spend ~3 days at RM, and ~4 days at Pearl.
To summarize, we would definitely go back to Pearl, and would recommend it to any couple who wants a sexy and fun lifestyle vacation, with the opportunity to kick back and enjoy each other's company (and all else )