"Best" is a very subjective term, and you will get as many different respones as there are dive shops in Key Weird. I lived in KW for 13 years and taught scuba for the college. I have dove with most of the shops and have occasionaly worked on some of the boats as a DM or instructor. Just so you and your Fiance' aren't suprised, be aware most of the boats in the Keys do NOT put a DM in the water. As your fiance is new to diving, if you feel you may want a DM, plan on hiring a guide. I would highly suggest you mention this when booking. Most of the shops will do 2 tanks on the reefs on the afternoon trips. It is also common for them to take snorklers, as well as divers, on the the reef trips.
I always preferred Lost Reef Adventures, 305-296-9737, Located on Margeret St, across from Half Shell Raw Bar. The Boat, "Dream", is docked right there as well. Dream is an older, but dependable boat with a platform at water level, making for an easy giant stride. You can expect competative pricing. They are rated for 16 divers, but rarely carry that many.
Captains Corner is is another favorite,305-296-8918, located at the corner of Green and Elizabeth, by the Conch Republic Seafood Company. Their Boat, The Sea Eagle, Is larger and the deck is about 5ft above the surface. Some find the giant stide a little intimadating. They tend to be about the least expensive and are some times crowded.
I like Subtropic as well, (sorry I don't have the number), located on N. Roosevelt and Garison bight. They have a couple boats,and tend to be moderatly priced. They have the longest ride to the reefs, as they are on the Gulf side of the island.
Dive Key West, has the nicest shop with plenty of easy parking and runs a very professional opporation. They do put a DM in the water on the wrecks, I am not sure if they are doing so on the reefs. There shop is on N. Roosevelt near the Sears shoping center. Their boat, "Easy Diver" is docked at Ocean Side Marina on Stock Island, about a 5 minute drive away. "easy Diver" is newer than many of the other boats and they have one of the shortest runs to the reefs. Dive Key West is usually one of the more expensive charters, but theytend to offer a few more ammenaties that may be appreciated by newer divers.
I would also strongly suggest diving the upper Keys. The reefs are healthier. I suggest either Conch Repulic (Send Captain Gary a message on this board) or Quiesence.
I hope this helps. I am jellous, because I really miss that crazy little island at the end of the road.
Safe Dives
Trtldvr
(Bob Guhl)