ive used EMS and microtec i would recommend both for the 26/30, if you where in oz i would say go for the microtec because with my experiance there is more people who know how to tune them well compared to EMS. they are both well priced (around $1500au)
i dont know alot about powerfc but the tuners i know dont recommend them so i didnt use it.
but all these ecu's are useless if your tuner cant use them, so i say use what he recommends or find a tuner who can tune microtec(or whatever)