The four stars do not reflect the quality of the bits, only that I only used a 1/4" bit in the router to clean some dados that were made with a cheap straight cutter. The bit worked well in soft I bought 3/8 and 5/16 collet bits to use two non-1/4 or 1/2 end mills. I don't have a CNC machine or router and plan to use it with handheld routers in homemade jigs. So far they do what I need, cutting cleaner and cooler than regular straight cut routers.