We did Navigator May 2019 for my husband's 40th. We really enjoyed it. If you're going to do the waterpark, make sure the kids are tall enough to actually do the slides. When we went, we could have gotten tickets for $24. I'm paying $42 in April on Mariner for my son's special 10th birthday trip. If the cost is much more than that I don't feel it is worth it. There just aren't that may slides in there to justify a high price tag.
In Nassau beware buying things - my husband is a big watch collector. The "great prices" they were offering him were things like $800 for a watch he could buy at home for $650. So know what you should be spending if you plan on a big purchase. There is a place called the Bikini Tiki Hut that is walking distance (if you don't mind walking) from the pier. We went there Thanksgiving week 2018 with 9 kids ranging from 5-16. The staff does a great job organizing games and scavenger hunts to keep the kids entertained so the adults can relax. The beach there is not big, so it's easy to keep track of the kids. They will rent you 2 chairs and an umbrella for $25, and have lots of alcohol specials. But beware the cost of food - there was no menu, and we ended up spending a lot of money feeding all the kids. Had I known, I would have run to the McDonald's across the street.