I have personal experience with both parkerizing and Armor Tuff on the same 1911. I own a great Wilson Combat 1911 (see sig pic).
Originally it had a parkerized finish which I loved. Extremely durable finish, rust resistant (or rust-proof is more like it) and good looking. The park tolerated a great deal of holster wear before showing wear around the edges.
This past summer Wilson did some warranty work on the pistol and refinished it in black Armor Tuff. I've followed the threads about "Armor Scuff" and was really worried about the finish. I do believe that they now lay a thin park layer underneath the AT to help stabilize the finish. I also believe that the AT finish chemically bonds to the metal and, even when it looks like it's worn to the bare metal, the AT properties are still there protecting it from rust.
Here are my observations about AT:
1. Looks great NIB. Flat black with an almost rough texture, kind'a like the dry lube on NIB USGI mags.
2. The AT finish has a HIGH level of lubricating properties built into it. A very slick finish. It's not slippery to hold, mind you, but it feels "different" than a park finish. I would trust this gun with zero lube -- the finish is that slick. The action also feels much smoother after the refinish.
3. AT cleans up really well. Just a quick wipe down and you're done. Heck, if I didn't have to clean the SS barrel, I'd be done cleaning it in a matter of minutes.
4. WEAR: Okay, even Wilson Combat admits that AT wears quickly at contact points at first but "quickly stabilizes." My experience leads me to believe this is true. After a summer of IDPA and practicing draws from a leather holster, there are exactly TWO points of wear on the front edges of the left side of the slide. Both points are through to bare metal -- one is about the size of two sharp pencil dots, the other is about the size of four sharp pencil dots. About 1/4" behind those marks the AT is worn slick smooth, but is still black. There is also a slight two dot wear mark by the ambi-safety. There is no other wear on the gun. The front slide wear marks showed up relatively quickly, but I think that things have (as WC puts it) "stabilized" after that. No major chipping behind the ejection port, etc. as was characteristic of the "old AT." EDITED to add that areas of the slide rails also have the AT worn down to bare metal, though the AT is still there protecting the metal.
Bottom line: I'm pretty impressed. The park finish seemed to scratch easier, but was more resistant to holster wear. The AT resists abuse very well, and the minor holster wear has "stabilized." If WC asked me what finish I preferred I would have said park, but I'm very glad in retrospect that I got an AT finish.
YMMV
EDITED for typos and to add a comment noted in text to #4.