I have the interlocking floor mats doubled at my quilting machine. I purchased them from Harbor Freight several years ago. I could never stand very long without them. I had to double them and I think it is because of the concrete floor. About 8 years ago, I was in Wal Mart and they had a couple of the kitchen mats, dense foam, on sale for $2.00 each. I thought...what in the world will I use them for? Well, the more I cut fabric and stand ironing, I know why I have them. I did put them down on the floor and stepped on them to see if they were good. Oh my, yes!
Best thing to do is to go try some at a local store. Most stores have a return policy. If you don't like them, take them back. A tip...don't fold the foam ones in half, they will break. I just put duct tape on the back, and still use it. I do agree that the beveled edges are nice, since most of us tend to shuffle as we get older. "smile"