Hahahaha....
That is one of the more stupid things I've heard. I'm not sure if you are serious or are an aspiring stand-up comic genius!
You'd be good at the latter.
Mate, ECU's do NOT make power. The tuning of an ECU does that. If you have say, 2 x 200HP cars. Both identical. If you install a Microtech to one and a P-FC to the other, neither will make more power than each other. I'm sure good P-FC tuners will be able to tune an ECU to make the same power as a similiar car with a Microtech. Also, you may of had such a large gain, but the person you stated that only had the 31rwkw gain with the P-FC probably got much better economy and ran a safer tune.
I would go the P-FC, simply because most tuners are more familiar with them when it comes to Nissan performance cars. Another advantage of the P-FC is the knock sensor, could come in handy one day, y'know...
Anyway, I hope you make a good choice, no matter what ECU you choose. Good luck