I had the square one. The mat was okay but it always came apart. I see this type on our guild free table a lot. I bought the Martelli 17" and it's excellent. I keep it on my cutting table. The mat is replaceable. It's sturdy and smooth rotating. I have the 10" Sue Daily one and rarely use it. I don't know but it seems the ball bearings in the Sue Daily one are plastic. It sounds like it. It has a good mat.