Really nice. We did 16 persons cruise for a week. Try to book a cruise that everyone is on for a week. For ours people got off after the 3rd day and others got on for the rest of the week. It gave us staying for a week a half day in the town to see some good stuff but ruin the flow of the trip. (Another safety briefing).
Also the last night we had dinner ashore but then went back out in the water to sleep on the boat. It gives the crew a chance to do things on shore but takes away from a grand finale of the trip.
Make sure to get sized for wet suits properly before departing as once you depart there may be no options to change. Someone on our cruise that got on after 3 days was in that situation and took mine at the first chance but then spent the rest of the cruise on the boat when all the others were snorkeling.
As nice as a cruise with only 16 people is that still means there are 15 other passengers on the boat. Other people are too slow (one lady had a broken leg and on crutches), we switched our our room on the main floor with hers upstairs. Others like to take a hundred pictures on a few hundred meter trail holding the group up. That's great but 15 others are waiting. Some or more then some are gross. In a small group after an outing there will be a plate of snacks. Take what you touch, do not eat other the plate and do not double dip should be normal but apparently not.
Both towns are dumps. Making a cruise much better option. But decide what size of boat you want.
No matter how you do it it will be expensive.
Food was great.