Personally, I view the two pistols you mentioned as having different uses. The 22A is good for match work and plinking as it has a single action trigger of good quality. The M&P22 is an understudy for your M&P service pistol, allowing less costly practice with a pistol that operates like your duty gun.
In order to figure out which to use at the match you mention, I would want to know the course of fire, whether rapid reloading is required, whether the stages are started from the holster, and questions of that nature.
Given that it is Ruger, I would imagine it would not be set up like a combat course, so if does not require combat manipulations of the pistol, such as presentation from the holster and rapid reloading, then I would get the 22A. Just my thoughts.