I understand where you guys are coming from. It's more my personal prejudice against anything other than stainless or carbon steel more than anything. That's just me, I'd rather have a stainless frame shooting standard pressure than an aluminum one.
Regarding the +P out of a short barrel, the chrono numbers I've seen myself from my Kahr MK9's 3" barrel will dispute what has been said in this thread. There is definately still a difference between standard pressure, +P, NATO and +P+ that I have verified myself.
Now, regarding the Rohrbaugh, for some reason the velocity numbers I've seen online are less than what I've seen and personally chrono'd from my Kahr. I don't know if perhaps +P would just be less of a benefit in a Rohrbaugh, than other guns will similiar barrel lengths. That may be so. I would be fairly happy shooting standard pressure loads out of a stainless steel framed Rohrbaugh, but I would prefer the +P capability.