I'm in a similar situation but haven't posted anything yet. We booked CN for New Years about a month ago. There was an amazing price by a company who were selling packaged to CN and CTI for the first time. I just couldn't resist the price because it was about $700-$800 less than any other supplier. My wonderful Travel Agent knows we love CSA and kept her eyes open to see if the supplier started offering CSA and CSS. We'll, needless to say they did and again the price was so great I didn't mind paying a change fee to get back to CSA. When I booked CN I posted that Loyal CSA fans were coming back to CN and how excited I was because CN was our first Couples experience and it held a special place in my heart. I was really looking forward to going back to CN but I got weak and that price for CSA was just too much for me to resist. I haven't had the nerve to back onto the website and confess my weakness. Feel like I should be going to an AA (CA?) to help get me strong again. - LOL.
All kidding aside, you've made a good choice and will love CN. We've been to CSS and really like the romantic feel of the property but the beaches in Negril are amazing. If you have time do a property exchange and take a look at CSA. Both of the Negril resorts are unique and have different but beautiful beaches.
Hope you have a great vacation.