I had a 1911 cerakoted. It's tougher than a teflon-type finish but still rubs off in high friction areas. I've had several guns plated with np3 by Robar. I've had their Roguard finish as well - tougher than some but rubbed off in 1-2 mos. on high points. NP3 is a good finish, but not as tough as hard chrome. I've had NP3 on a 1911 for 10 months now - it's scratched up from carrying in a smooth leather holster and has speckled shiny spots where it's been rubbed on. NP3 cleans easier than anything I've seen.
The thing to keep in mind if you're considering the Robar route is they seemingly can't follow instructions. I sent explicit written instructions to leave my stainless match barrel bushing alone (it came back apparently nitrocarburized or something, don't know what it is) and to remove my grip screw bushings and NOT use loc-tite or anything else when re-installing them. They came back loc-tited. I also didn't end up getting the monthly special I'd applied the code for and written on my form, and had to wrangle back and forth with them for a week or two to get the special. One plus is they do have a decent warranty - when the Roguard I had on one gun came off after a month they re-did the gun in NP3.