Crankcase evac. Question?

Is it not true that some of those evac systems actually cause pressure at low RPM's instead of vacuum?
I read that somewhere on a hotrod website so it must be true.:D
So maybe if it's a daily or weekend around towner it would best be served by a standard PCV system, no?

I'm using both right now. The PCV and the pan evacs. So far, nothing has gone wrong. Yet. I'm sure if something is going to go sideways it will happen to me!