I would use both. There are more features with Ecu Editor that you can modify, including the ability to turn off the ram air compensation prior to the tune and re-enable it after. And of course, timing, speed limiters, rev limiter, etc. Many more features with Editor that you can modify that would be beneficial to the overall tune. And yes, a lot of tuners won't mess with it for a variety of reasons. The PCV does fueling, and fueling only. However, in the case of fueling, it is not about the box, but the software that differentiates which one is better. Dynojet's tuning link software, used in conjunction with a powercommander, enables the tuner to generate a/f curves at every throttle percentage. This makes for a more linear and complete map . . . it is also easier on the bike while it is up on the dyno. Less time, less drama, less wear and tear. IMO, the tuning link software -which not every tuner can afford - is what makes the difference.
Then again, if you ask two technicians, sometimes you get three opinions!