I have a Gemini PDA, and it's not bad. I could wish for an X server to run Emacs against, but it works fine in terminal mode; I could wish for a more comfortable Linux-on-metal experience, but Termux and Firefox on Android are easily good enough. The keyboard is excellent.

Too bad it came along a decade after I ceased to really need the kind of road-warrior sysadmin capability that such a device excels at providing. I'm still glad to have it.