You have to decide what is important to you. The au naturel wasn't a big deal for us so CN wasn't automatically included. With my husband just getting over knee surgery, flat was best for us with plenty of walking to help rehabilitate so the nice big beach at CSA was important. Sports?? CSA has the best sports complex around, although we had to be careful. The sprawling lush grounds is what drew us to CSA. Now that he is fully recovered, we are trying CSS to enjoy the Ocho side and the stairs.
We found that CSA was a great resort when it was just my husband and I as it was easy to find a private tucked away spot where as CN seemed to be better when we traveled with a group. CN had a much bigger pool, but CSA had much larger grounds and gardens to walk through. CSA offers more food options including the veggie bar which was nice for a light snack in the afternoon.
The other thing I noticed was that more of the rooms at CSA seemed to be facing the ocean where as a lot of the rooms at CN faced inward towards the gardens. Just sitting on our patio during a rain shower was nicer at CSA vs. CN where we barely went out there due to minimal view of the ocean in our Deluxe Ocean room.
Long and short, it depends on what you're looking for, but if we were to go back to that side of the island, we would probably book CSA for just the two of us.
Looking forward to CSS in just 31 days for our first try of the other side of the island!