It depends on your cam. A stock or mild cam provides so much vacuum, the PVC will not make much difference. With my lumpy (long duration, lots of overlap) cam, vacuum is at a premium for my brake booster. I have much better brakes without the PVC connection. I have also installed an electric vacuum pump to help out when the vacuum drops too much. Sliding off a mountain road one time was enough!
I used the Moroso system to draw the fumes out of the crankcase. The tubes from the rocker covers are connected to the exhaust headers instead.
It is much easier to tune the carb without the PVC (steadier vacuum signal) and you make more power (richer mixture). However, it better be there for the smog test!
Paul