I like the 193 for soft targets up to 100 yards plus, because of it's lethal fragmentation.
Also, I live in the California Sierras and the steel cored anything can be a real fire hazard during the summer months, if I hit some blue granite near dry weeds.
But, if I needed to have penetration through something like a car door in a fire fight, I would want the heavier steel cored 855, which also holds it's accuracy out past that of the 193.
Up to about 130 yards or so (IME) they are both equally accurate. But as you get beyond 150 yards the 855 maintains it's grouping better, and progressevly so the farther out compared to the 193.
Sometimes I can find PCM M193 for less than PCM 855 and other times it's just the opposite.
Recently I bought a 1000 round case of PCM X-Tac M193 for $369 delivered from ammoman.com, and found PCM X-Tac 855 for, like ..... $330-something delivered, when googling for the the best price on the PCM 193 X-Tac.
I also like the PCM X-Tac because it uses boxer primers, and that makes it easier to sell my "once fired" brass for about $.10 each ...... which gets me closer to the price per round if I reloaded for plinking (which I just don't want to do).