I really appreciate being able to buy a quality flex plate for my printer from a US company instead of picking from one of many "no-name" brands on Amazon, etc. Also I like that WhamBam carries sizes for my Ultimaker printers. Their sizes are usually hard to find.
I'm used to printing with PEI so I was curious to see how the PEX performed. So far, it's been great for me. I did need to scuff it for best adhesion, I found that out after some quick research, I think it would be good for WhamBam to leave a note explaining this with this plate.