Thanks for the kind words. Only did Key Largo once, Sept. 2013, 20 dives (2 2-tank boat trips/day) with Rainbow Reef Dive Center over 5 days, and loved it.
It was my first really long-form trip report. Averaged cost/dive was a good value, and with me, wife, kiddo and mother-in-law packed into a single hotel room, total trip cost was really good. RRDC has moved a bit since then (though I heard they hadn't gone for); then they were at the end of our hotel parking lot, so I could be gone diving without needing a vehicle while the family roamed. The Keys are not a shore diving destination, but sounds like you're looking for boat diving anyway.
Shallow reef diving over a horizontal 'floor,' rather than wall diving, pretty nice reef growth, pleasantly fishy with more fairly big stuff than I recall from Bonaire, and the guide was included free (and when the boat had plenty of people, I recall 2 guides, each leading a separate group). Morning dives had an option for deep trips (the wrecks like
Spiegel Grove and the
Duane, which I enjoyed though they were shorter dives). Reef diving features viz. around 50 feet; not up there with Bonaire, Cozumel or the Caymans, but good enough. If you do the deep wrecks, take gloves, because the boats attached to permanent mooring lines with things growing on them (I assumed barnacles, but someone suggested later they may've been 'razor clams' - either way, you want gloves).
RRDC had a strong reputation, and was very well-known - I understand they train a lot of recreational diving professionals. Their boats were fairly big, and while I didn't consider them 'cattle boats,' they weren't 6-packs. But it's been several years and I don't know what services they may have added. I booked a dive package + hotel through them; they can customize a package for you.
A number of recommendations over the years were made for an op. called
Quiescence Diving Services aiming for those looking for a 6-pack boat, albeit without a 'free' guide included.
From this forum, the upper Keys op. I think has the most overwhelmingly consistently strong positive reviews is
Conch Republic Divers (though I didn't read of them offering a free guide) - they're a little further south, in Tavernier. They are one of the few op.s I read about where almost every report about them is gold (the Peace boat in California the Captain Sl8er's boat out of Jupiter, FL were like that when I researched those areas).
I'd happily book with Rainbow Reef based on good experience, or Conch Republic based on powerful reputation, for what I'd want to do (a lot of guided diving crammed into a few days). Planning the RRDC trip and the logistics once there was easy, and I like easy!
If I didn't need a guide, wanted a smaller boat so I'd have more say in where we went, I'd at least start by checking the latest on Quiescence.
I didn't research any of the op.s about solo diving. I've heard sea conditions and water temp.s fluctuate seasonally much more so than Bonaire, but I don't know all the details. It is possible to get 'blown out' some days.
Sorry I couldn't help more from 1st hand experience. I'd love to go back, but so many diverse options keep calling! As Caruso mentioned, there are a lot of folks with a lot more experience than I've got, so hopefully they will chime in. Helps make threads better for other people who run across them doing future trips.
Richard.
