If I had to choose, CCI mini-mag HP's. While the Stingers, Vipers and other hyper-velocity .22's do boast a significant increase in velocity, they do this in RIFLES by using slower powders. They gain nothing in handguns, and in some cases actually loose perfomance from short barrels. In my own testing, fired from barrels under 6", the mini-mags actually produced more energy than the Stingers. Also, the stingers use a longer case and are pushing the limits of .22 LR COAL; they don't function well in some autoloaders. Also, the CCI mini-mags have proved to be more reliable than most other .22 LR ammo in my experience. They cost 3 times what most other .22 LR does, and I believe this to be the result of better components and better CQ. I don't recall ever having a dud with CCI premium rimfire ammo.
before I got my P3AT, I carried my NAA mini revolver form time to time. I always had it stoked with Mini-Mags.