I also visited Maldives the first time in February 5 years ago.
Here is my post to this forum before making my decision and the answers to it
http://wetpixel.com/forums/index.php?showt...gungen+maldives
Based on these information i selected the Sun Island Resort which is geographically located close to the Southern edge of the South Ari Atoll.
I preferred this particular resort due to it's big size and variety of non diving activities. However the diving boats were too crowded.
Probably White Sands would be a better choice for diving since it was a smaller resort.
It looks like the ex White Sands is now the Diva Resort and quite expensive.
I remember that we saw Manta's in each dive and met once a Whale Shark. Other than the abundance of mantas i do not remember a very dense macro life. However even stuff like ghost pipe fish were occasionally available during dives. However since manta's are the highlight of South Ari especially in this time of the year it is a though decision to dive with a macro lens.
Hope this helps.