The M1991A1 stainless finish is what Colt calls matte stainless. It's a gray rather than silver look, and it has virtually no gloss. I would classify it as a utility finish. I don't really like it, and I plan to have mine polished out in the flats and put a bead finish on the rounds, much like the XS or Gold Cup stainless pistols have.
Scott Mulkerin refers to the Colt matte stainless finish as being like blasting the finish with driveway gravel, and I don't disagree.
The finish is ugly, but the pistol underneath is another matter entirely. I've shot 548 rounds so far with 0 FTF, 0 FTE and it rings a 10" gong every time at 50 yards with good ammo and when I'm serious about it.
One word of advice, though. If you're looking at a Colt that's relatively new, don't worry about it's function, but look carefully at the sights. The last several pistols I've seen out of Colt and the Colt Custom shop have had very poor sight installation.
Best of Luck,