Yes, it's by far the best home-finish I've ever used. It's far better than the bake-on gun laquer that Brwonell's also sells.
I've used the can stuff and you can do a couple rifles with a can.
I've used the thinner liquid stuff that you need an airbrush/sprayer for and it builds-up much thinner and is better for good looks, but take more work.
The finish looks similar to the HK black paint look.
The key is in the prep of the metal. You really need to clean the dogcrap out of it and make sure you don't have ANY rust or ANY grease. Brake cleaner works well, but I always used denatured alcohol afterwards to insure that there wasn't any residue of anything left behind. Get the metal clean and dry. This is the secret to getting good results with this stuff.
If you've done that, then it's a snap. It will also be VERY resistant to scratches, etc. I like it better than the finish that most guns come with.
I would go with the spray can for the AK. First of all, while hassle with a compressor, sprayer, etc for an AK. Second, the thicker spraycan product will hold up better to abuse.
Prep the gun, heat the gun, paint the gun, and bake the gun. Done. Be ready for some serious stink in the kitchen though. The baking process isn't odor-free.
With the liquid stuff you can mix and match the liquid to get custom shades of the different colors (black, gray, green, tan). That's way too much work for your application IMO.
Beadblasting to bare metal will obviously get you the best results. I've put it on over park an anodizing on some ARs and it didn't seem to matter any though. For a using gun, I'd just knock off the surface with sandpaper and go to town with the rattle can of Gun-Kote.
The short answer is, Yes, it works and is worth the price. Just follow the directions on the can and you're good to go.
Ross