The Amana Carbide Spiral Coating Router Bits had me impressed. As a result of my tests, I determined that these tools WERE the best cutting tools I have ever used. The spiral coating really kept any buildup from happening and the stainless steel made it tough enough to last for a long time .The only downside was the higher cost, but the quality of the cuts made it worth every penny. Overall, I highly recommend giving these cutting tools a try..