I just spent 8 days shooting with a prototype NAD300 housing in the Socorros of the west coast of mexico. Almost all big animal, big current diving. Before the trip I did a couple of shakedown dives here in Puget Sound in cold water with the system.
Overall it is very rugged and well-made. My prototype had control issues that are being attended to. Weight has been reduced by .2k. I'm trading up to a D300s for the final. I'm not going to go into details, except to say Ryan and Nauticam are well on the job to smoothing out the wrinkles on an awesome line.
The optical viewfinder is terrific, allowed full finder viewing easily, even with a sort of one eye on the animal, one eye in the viewfinder approach.
I mainly shot two lenses; the Tokina 10-17FE behind a Sea & Sea Optical Dome Port and SX ring as well as a 17-70 Macro Sigma with the same set up with the addition of an RDX ring. NauticamUSA knocked out a zoom gear for the lens, which I'll be trading in for the newest HSM/OS model when it ships. I did one dive with a Nikon 60 micro and one with a 105VR, both worked great, and the manual focus for the 105VR is sweet. Port changes are fairly fast, you do need to take the camera out, but otherwise it's pretty quick. Cards & batteries can be changed without removal from it's tray.
I used 2 YS 110a strobes in optical D-TTL mode which seemed quite accurate within the confines of TTL. One cool thing is that you can shoot at 1/320sec TTL/FP in optical sync mode with the Nikon.
I am the NauticamUSA PNW dealer here in the US (and a WetPixel sponsor) and would invite all inquiries.
Here's a few shots - I have shot a D80 for quite a while, but just starting out on the D300, so be kind... ;-)





Jack