The boox air 3 c is currently at the top of my list of useless gadgets I want to play with for a week before placing on the retirement shelf.
I sadly recently broke my ultra c with the pressure just from putting on a new screen protector using a cardboard applicator. I was mainly using boox notes with the stylus to read pdfs and pressreader on flights and that was a decent experience.
My other criticism is prior to this just having the magnetic pen attach itself damaged the finish on the side.
I'm glad you like yours, but the appeal wore off quickly for me and I would suggest any potential buyer familiarize themselves with reports of experiences of trying to get service or warranty on these through the company.
I have a reMarkable 2.
My primary problem with it is the battery life. If you leave it on, it will, after a certain period of time, overlay a banner on the screen saying it's turned off because of inactivity.
But the banner appears to be lying. Leaving it in that state rapidly drains the battery. If you want the battery to last, you need to manually tell the device to shut down, at which point, instead of displaying whatever was last on screen plus a banner explaining how it's shut off due to inactivity, it displays a different screen saying "reMarkable is powered off". At that point, the battery stops draining.
I can't understand why shutting off due to automatically-detected inactivity isn't supposed to take the device out of "actively drain the battery" mode. It seems like a huge, unforced usability failure.