I can categorically tell you that the grip on the Jet Black is a lot better than the other colours. It almost feels like it's already in a case, which I love.
I have no pro-Jet black agenda, I don't feel any pathetic need to big up the colour I chose and belittle the ones I didn't.
I've always found the iPhone 6 and above to be a bit like holding a bar of soap, the Jet Black grips in my hands very nicely.
Thanks, yeah I'm the same, never been able to comfortably hold a 6+ without a case. Well, I mean from a sliding around factor.
I like the look of both the JB and the MB. So decision time I guess.