I used plastic 2" necked PB for years with mixed success. They used to be relatively cheap but they are unreliable. They leak mainly due to pressure and especially in warm weather. The cap washers are a nightmare and the taps are not fit for purpose. I had to leave just filled and primed barrels on the draining board if we were going away for a few days. So I moved to bottling but since I joined this forum have bought two Cornelius keg which are great.