We were at CN in September and stayed in a Garden room in Building 3 - 3rd floor. The only time I found it noisy was the first night (Saturday) - cars zooming up & down the main road just on the other side of the tennis courts until 3am. I thought about asking to be moved but we were totally unpacked and I'm too lazy. It was better thank goodness the following nights until our last night - Friday. I guess the weekends are nosier than weekdays.
We live in the country at home and don't have car noise so it was kind of weird to have it at our vacation resort.
We are booked again for next May & September and will once again ask for a room in Building 1-5 so we are close to the dive centre but hope it's not building 3 again. This time I know more so we can change at time of check-in.
Couples Negril - September 2011, 2012, 2013 and have just booked 2014
Scuba Club Cozumel - Jan, Apr & Nov 2012 and Jan & Nov 2013
Cobalt Coast, Grand Cayman - May 2013
Retiring & moving to Cozumel, Mexico in early 2014