I will try to give my opinion. If you’re done with all other modifications like exhaust/airbox and you have someone experienced with a matching map I would absolutely prefer the ecu flash.
If you’re planning further mods, you’re skilled and have access to a rolling road/dyno the Power Commander would be the best decision.
Because you asked that question the flash would be probably the best for you. An experienced tuner will have a dyno to proof the results before and after the remap. Closed loop at lower revs will also be optimized for relaxed city crossing and smooth acceleration on the open road.