I've found the IP coating to be fairly scratch resistant, but I haven't owned my Black IPs long enough to provide long term test data.
I like these watches for their appearance and the feel of the black IP in hand and on the wrist, also very stealthy, nice matte finish.
I have to admit that when I'm wearing a black IP watch I think twice about movements that might bang it. It's almost second nature now, like Spider Sense = Black IP Sense.
My GL-7000RF is black IP, great watch, I've got the black IP giez coming in soon, that one is only IP on the case with rubber strap.
I never think twice about banging Gs with rubber straps or traditional stainless steel bracelets.
cheers