I shoot live firing service style pistols competitively, and have done so at a national level for some years. (Norway, still legal here) and have been looking for an indoor trainer for some time, but havent found any that have the required accuracy for what we do in competition.
I would consider 1" groupings at 10 meters an absolute minimum requirement, and most BB firing replicas I have tried struggle to group below 3" at 10 meters.