I have been thinking about buying one so will be watching this closely. Next trip on amazon to buy.

I have 2...green Omnigrid and gray Fiskars". Both 6" and love them both. Omnigrid in a circle and Fiskar" square. Depending what color I'm trimming determines which mat I use.

It took my 16" Martelli Roundabout to a retreat. Several quilters used it and each ordered one before the retreat was over. The square rotating mats were always on our guild free table. Last meeting we had there were two of them. No one took them so they were donated. I know for sure as I am/was free stuff chair.

I'm really glad I read this thread. I've been looking at rotating cutting mats to purchase. I would love to buy a Martelli mat, but, gosh, they are pricey! The advantage is the mat is replaceable so maybe in the long run it's worth it. One thing for sure.. I want to get a round one. Several times I've heard people complain about the instability of the square ones. Makes sense to me. I visualize two squares twisted as diamonds in opposing directions and see corners unsupported. (If that makes sense. Lol).

Another option I've considered is making my own, as someone else mentioned. Find a lazy Susan and glue a mat on top. That appeals to the "I made that" said side of me. Lol.

I have one & is most used when I square up 12" blocks. I love it.

I have always went by this: When you buy an item that lasts and does the job each time then you forget what it cost. When you buy a non quality item that breaks or never does the job right you never forget what you paid for it.

I have a Mathilda that I keep to the left of my sewing machine. It's really handy in that spot.
My first one was square and it went in the donation box as soon as I got my round one.
My Mathilda was bought when Craftsy used to have fantastic sales. I also got 2 Supreme sliders for cheap.

I like mine a lot.

I miss the Craftsy sales. I wish I had bought more. LOL

I have an Omnigrid and I love it. It's wearing out, so it's time to buy a new one.