Something I have played with is running both but disconnecting or backing off the adjustment on the front brake. That way you can still add some rear bias to get the car to rotate. I prefer to run only mechanical brakes for the reasons you stated but this also works.

Another advantage to running both is that the mechanical brake usually is more sensitive to adjustment so I found if I got out on the track I could vary the amount of rotation just by adding a couple of percent on my brake epa.