FWIW, This spring, I purchased a used Aquatica D200. I was moving to this from a Oly 5050. I used for a week in Lembeh and a week in Komodo. My camera bag was stolen on the last leg of the trip home (though the camera was in a separate bag) so I'm now about to purchase a new housing.
The Aquatica housing functioned quite well. The only control that I found to be difficult to operate was the AEL/AFL. The control wheels operated well, though maybe not a precisely as I would have liked. The only real downside to the housing is it's weight. The Aquatica is significantly heavier than the other aluminum housings. I used Stix arms to counteract, but with macro, where I used only single 5" arms, the housing remained fairly negative. It's also not as compact as some other housings. It's also not as nicely finished or as precise as some. But it seems a very good, functional housing.
Now that I have a check from my insurance company, I am going to replace the stolen housing, but probably not with an Aquatica. My biggest complaint about the move to an SLR is the increased size and weight, so I'd like to minimize that. I've managed to get my hands on the Nexus and S&S housings. At the moment, I'm leaning heavily toward the Nexus. I was very impressed by the fit and finish of the housing and the obvious precision of its manufacture. It shares the Aquatica's defect concerning the AFL/AEL button access, but otherwise looks like a great housing. My preference for the Nexus over the S&S is the availability of a fiber optic connection to the strobe. With Inon Z240s providing optical ttl, this is, for me, a decisive advantage. I am also considering a used Subal ND20. I've heard nothing but good things about them but haven't been able to put my hands on one.