The 52-600 series is a great but often overlooked series for plastic routing. It has a double "O" flute design which leaves a smooth clean finish. The two edge low-helix spiral is less aggressive which means it can be a problem solver if you have issues with material hold down. It is also a good series if you use laminates as it will exert less pull on those as well. The Onsrud 56-600 series is a similar series with a straight edge design.