It all depends on use (and misuse).
Barrel life is very much a factor of round count, rate of fire, and cleaning. Normally in barrel life we are discussing throat erosion. Hot loads, high rate of fire, extended firing that gets it hot and keeps it hot, etc...will all encourage greater throat erosion regardless of material or coating.
That said, in general terms with EVERYTHING being equal, stainless will outlive moly, and chrome-lined moly will outlast either std moly or stainless.