We just stayed on Fulidhoo for 8 nights in January and it was wonderful. We booked everything through Fulidhoo dive and they were amazing at arranging all the details for us, of the diving , transport from the airport and our stay at Kinan retreat guesthouse.
The dives were fantastic and Ali who runs the dive shop with his wife is very professional, the boats is small and I don't think we ever had a group of more than 6 so it wasn't crowded. He has been diving the area for years and knows it very very well.
Fulidhoo itself was lovely and very quiet as it has a population of less than 500 and perhaps a max 50 people staying at guesthouses on the island. The entire island is very clean and incredibly safe. The beach is small but never very crowded , with beautiful sandy bottom only 6-8ft deep at the deepest for as far as you can swim. There aren't big waves because of it's location on the atoll so it would be good for little kids.
At the time we were there a family of 5 with kids age 5-8 was staying at our guest house , they had been there for a month and the kids seemed to be having an amazing time. They had been there the previous year too so it is very family friendly.
The cost itself was very reasonable and the package we arranged through
http://www.fulidhoodive.com/ our 15 dives each, 8 nights stay in the best room, and full breakfast and dinner each day. Lunch at the guesthouse would have been $10US each but there was also a few other guesthouses/cafes to eat at too which were a bit cheaper. There is a ferry but the speed boat to the airport only takes about an hour and costs $50 US each. This was one of the reasons we picked the island. We didn't want an 8 hour ferry or an expensive seaplane trip.
Fulidhoo isn't a luxury place to stay but it's a quiet little piece of paradise. The food is limited because most of it needs to be imported to the island but we didn't go there for the food. I would highly recommend a visit to anyone.