I had a C&R back when I was buying a lot of milsurps, but I've since let it lapse. In addition to the usual perks in shipping milsurps, it can also be very handy for the discounts at Midway, Brownell's, etc. However, I did not like having to keep the log, and was glad when I could let it go. Asking for a buyer's info for the log book caused a few deals to fall through - who wants to give out their personal info to someone they don't know? I couldn't blame them.
I have mine. I've had it since 2006. Its very easy and painless to apply for and it pays for itself. Its quite nice to have guns shipped right to your door.