Its becoming my more popular than you may think. We did it at Pine Tree in 2012 and tees/apps in 2013. We will be doing it at my next Superintendent position in 2016.
Maintaining 419 and Common can be very difficult. Each grass takes up pesticides and fertilizers differently, grow more aggressively at different times, and playability can be great hindered, especially around greens when trying to put an/or bump and run. Depending on growth, common can scalp badly while hardly cutting the 419.
Many courses are regressing to MORE aggressive turf (Celebration at C3) to minimize any reoccurrence of the common.