I have used most all the different types and brands of rotating mats at retreats. The best one was the Martelli Roundabout. I have the large size one and now there is smaller size. I hear other quilters at retreats using the Martelli rotating mat say this is great. I have to get one of these. I see the square rotating mats on our guild free table several times a year. It does not tilt, get loose, or come apart in use, and turns smoothly. Watch for sales. The mat part is replaceable if needed.