I love the X3, light enough I can carry it around without noticing it. Battery lasts forever. I don't feel the need for a backlight at all, I love how simple this is.

I know people favor the X4 for the usb-c, and I'm all for universal charging cables. But in my experience the usb port is often the first component to fail in something like this. And that seems super annoying to replace. The pogo pins on the other hand are unlikely to fail. And the cable is not proprietary, you can get compatible cables on Amazon/etc.