In the process of fitting these and just tried the rear window cam for position and picture quality. It appears to give a really good picture through to 90% tint glass - at least as good as the VW reversing camera - so I am very pleased.
Getting the rear window camera cable through the rubber cable tube, between the hatch and the car roof, was a bit of a fiddle, but the rest of the job looks reasonably straight forward. I have the hard wired kit, which includes piggy back fuse holders etc, so should have the system working soon.
I didn’t contact Tiffany, Mike, but the forum you mentioned was full of very negative comment. Like a lot of forums, it seems to be just an outlet for people with, what they see as, duff products. So far, I am very pleased with the quality and function of Nextbase gear.