the crit chance seems to be bugged. Apparently it adds 0.25% chance of a critical hit, instead of multiplying your crit chance by 1.25 like Ninja does or adding a straight 25% chance like Light Touch does.
http://fallout.wikia.com/wiki/Talk:Certified_Tech
http://fallout.wikia.com/wiki/Talk:Certified_Tech
I figured this would be useful for a steady supply of sensor modules for stimpack auto injects and fission batteries for creating Energy Cells but if the critical chance is bugged as he says then I dont think it's worth it.