Star Citizen. I'm less disappointed in the tech demo than how Chris Roberts has handled the business end of it.
I grew up on Wing Commander, Privateer, Starlancer, and Freelancer. I still have all those games on physical media with original boxes. And the Wing Commander CIC is the one website I still visit daily since 1997-ish. So when Roberts pitched a new space game back around 2012 I was thrilled. Well, we all know how that turned out. I've given up waiting for any release of Star Citizen and Squadron 42.
I recently picked up an Xteink X4 for $55. Flashed the Crosspoint firmware on it. Crosspoint just works and has no bloat. I love being able to set the device and send books via the self-hosted web interface. Sending books via wifi from Calibre works too.
Buttons on the reader are nice. I actually prefer not having a touchscreen for something so small. I do wish it had a front light though. This turned out to be the less-expensive-non-Android-just-an-ereader alternative to Boox that I was searching for. Loving it so far.