I've been using a Supernote Manta for the past month and I love it. It's not a full-on computer, and it has its own UI that discourages you from treating it like one, but it is in fact an Android device. I've installed Syncthing and a few other small niceties, and it is amazing to be able to carry a big collection of PDFs around with me that I've curated on my laptop, desktop, phone. One of the "native" apps is Amazon Kindle, which is great, because I occasionally want to read one of those books on a bigger screen. The pen is good, and feels fine, although I prefer the feel of the ReMarkable.
Downside: there is no backlight. Others claim that the screen updates are too slow to make typing practical, but I personally don't think that. I installed termux and I think it's fine. Screen updates are no worse than SSH over a cellphone connection. I have not really found a good RSS reader for it yet, though...
Boox is fantastic. I have the Palma and it's been very enjoyable, since it's pocketable and has excellent power management, so despite being android, the battery can last 1-2 weeks.
Boox devices are nice, and the stock e-book reader is actually quite good.
The firm's support is decidedly sub-par, however, should you encounter issues. I'd advise not splurging on their higher-end (larger) devices on the potential lost investment. Though a 13" screen is quite delish for reading technical articles.
I used to call everything a conspiracy theory, but then Glenn Greenwald published
"No Place to Hide: Edward Snowden, the NSA and the Surveillance State".
Now i know that reality is worse than the worst conspiracy theorist.