I have a Profec B spec II right now, and I don't like it terribly much. It DOES have a lot of features, and it DOES do a very good job at holding boost, but I hate having to re-tune it for altitude and temperature changes. If it's -10C one day, and +5C the next day, my boost settings are all out of whack. I could set the limiter on the unit, and use that to control the boost, but to me that's just a half-assed way to compensate for temperature variations. Also the limiter defaults to 1bar every time you power cycle, until you hit a button on the unit. That just annoys me, so I usually leave the limiter off.
I'm currently looking for an EVC V to match my A/F Knock Amp.