Chris U.
Yelp
First class dive operation. I'm an experienced, advanced, deep - but non-tech - diver and have joined their double-dip wreck dives twice. The dive boat is large, comfortable, well-kept and clean enough to eat off the deck. The staff is highly experienced, friendly, light-hearted, but 100% focused on safety.
If you're diving solo here, they will require you to pay for a guide (which I think is $40, so not too expensive). Given the complexity (and potential danger) of the dive sites they visit (Spiegel Grove & Duane), a guide is a good idea anyway, and their guides are experienced and professional. Sam was my guide on my last visit and I felt as if I got a guided dive, a history lesson and a mini advanced wreck class all in one.
The first dive was a fun, "light" penetration dive, which also served as a skills assessment for Sam. Once he understood our small group's skills a bit more, we did more advanced penetrations. These were still straight-through, lower-risk penetrations, but most certainly fun and interesting. Tech divers have the option to do one long dive, should the wish to go that route. (It should be noted that no one was forced to do a penetration dive and the group agreed on the type of dive that we wanted to experience)
I have not utilized them for shallower dives, but their reputation and feedback is excellent for those as well. I would not hesitate joining them on a less advanced dive if I didn't want to go deep one day, or if I was diving with less experienced divers.
The shop is well-stocked and the gentleman working the front desk way very polite and helpful. The boats are 5 minute drive from the shop and there is plenty of parking at both locations. The boat location has the bonus of being next to a good seafood shack, as well as around the corner for the Buzzard's Roost, which is my favorite go-to for post-dive grub.
I highly recommend using Horizon. If you're staying in Miami, they're in North Key Largo, so the drive is only an hour. It's most certainly worth it.