Sharing my own experience with NiMAR, as it might be of use for other people out there.
I dived with their NI6D (housing for Canon 6D, rating 60m) and I liked it, though it was my first housing so hard to compare. Unfortunately, it failed and flooded my equipment when I reached 20m, after my 4th dive. I contacted NiMAR's customer center who ignored my emails and phone calls for weeks, until they told me to ship my housing back. They performed testing and concluded everything was fine, so I would pay for the housing electronics damaged in the flooding. I requested to be contacted so I could at least explain the details on how the housing failed: not only they never called, but they threatened me to sue me if I wrote a bad review instead..
In the end, I will never know why my housing failed. Maybe it was due to a mistake on my end (after all, I am a new underwater shooter), maybe a problem on the equipment. But what I know is that NiMAR, on top of having a horrendous customer service, does not want to hear customer feedback - so can not possibly be serious about improving their products.