According to Jim Carmichael in the book 'The Modern Rifle' (great book from the 70's BTW), regarding stainless vs carbon barrel wear, stainless has an advantage in that the lower carbon content in the stainless alloy results in less surface 'carbon burn-out' (i.e. erosion) in the throat and thus longer barrel life. This is of course in regard to rifle barrels, but I'd think it also applies to handgun barrels as well.
It sure is more resilient to ham-fisted handling and cleaning methods too
Dave