They are expensive but they are definitely worth it. My first one was a big one, then I changed machines and the opening wouldn't fit, my new machine had a wider area. My husband has a saw that can cut smoothly through acrylic so he shaved off some of the acrylic until it fit. I can now use it on both machines, the slightly larger gap doesn't cause a problem. Now I was told by the supplier that there was NO WAY that could be done and it would knock the table off balance, etc., but it's works just fine.
I have since bought 2 more smaller ones so I can take one to class with me and have one at home too.
To keep them from getting scratched, I cut down an old pillowcase and cut slits in the top, threaded a ribbon through to use as a drawstring, and store the small table in that. The bigger table fits in a pillowcase without cutting it down.
These tables last forever, which is probably why they are a little pricey, they don't wear out. I've had the big one for 20+ years and it still looks new.