On the thread corrosion topic, I would like to note that there will always be corrosion when two dissimilar metals are put together then immersed in saltwater. Every aluminum housing I have ever owned (including most major brands) has had handles and other attachments secured with stainless steel screws, and all of these have shown a tendency to corrode and either disintegrate or weld themselves together over time, in spite of meticulous rinsing and soaking. I have not tried the teflon paste, but I have used a product called Lanicote for years with great success. The trick is to disassemble the housing parts and coat all the threads with whatever type of grease you choose before ever taking the housing into the water. This begs the obvious question: why can't the manufacturers do this? For whatever reason, they don't, and you should. The only other way out is to go with Ikelite, or other non-metal housing.
All the connecting holes in Subal housings are not directly threaded. The holes for the handles, tripods and top mount are filled with Helicoil systems (a self thread made in aluminium filled into the hole by the Helicoil technology). This way a stainlees steel screew does not get directly into contact with the aluminium housing and will not corrode. Just a little example of the quality in technology of a Subal housing. Can't really say anything about the Nauticam, except that when I checked the current Nauticam D4 against the one from Subal in a recent dive fair, I felt that the Nauticam was more bulky and less ergonomically than the new ND4. But cerntainly just a personal impression on a high level of both housings.
And the inmprovements Subal made over the last few housings are really impressive, as Alex already mentioned. In addition, if using all ports and extension rings with latest type 4 style, then also a full port lock of port and extension ring is available (not in my case since I am still using type 3 ports and extension rings on the type 4 housing,connecting both port adapters). I also noticed recently when testing the leak warning that sound and sight is now effective (a sound beep in former N3 housing was not given, I believe). So for me a change in brands was never a question.