As you point out, the "writing UX" was so astonishing, it was probably the quickest "adoption" of any major tech upgrade for me.
I wrote some notes on my experience and the transition from paper here: https://jessmart.in/articles/remarkable
Although that only helps to zoom in to one spot, if I were to try using that to read a page where the font is too small, having to shift the page left and right while zoomed, it would be a nightmare to read a document.
My gripe is I cannot switch the device to show a PDF in landscape mode. Then at least pretty much all documents' fonts would be large enough, if I use the height of the device for the width of the PDF. Then I would only have to scroll down and only after reading half a page. That would work well, scrolling left-right-left-right-.... while zoomed in does not, unless the page has two columns of text so that I don't have to scroll right-left-....
I use my RM2 mostly as epub reader. For the price - I got the preorder discount - it was the same or even lower as other pure readers of a similar size.
The software does have some weaknesses, for example sometimes I have to edit the epubs and remove some CSS background color because it ends up black on dark gray (unreadable of course), or it has set defaults for font, line height and such settings and I cannot set new defaults so I end up setting those for each and every document I sync to it anew. Still, it's acceptable for me, it's just a few (now muscle memory) clicks. To sync I sometimes have to start the Windows app to which I added a document a second time before it uploads it to the cloud server. That too now is a muscle-memory action. I hope they fix it some day but it's not a deal breaker.
I did a bit of writing and that just works and feels very good too. Other than the base use cases the software is very barebone. As others have pointed out, that's a goal. The device does everything I expect from it, which is just some basic writing and the epub reading. I can send webpages to the device (while it's online) by clicking an extension icon in the browser, which I do for RoyalRoad chapters, for example. WebToEpub creates epub files for entire Webnovels, which have to be uploaded using the Windows app though.
I'm surprised they pulled this one off.
I just refereed a research paper with complex (color!) graphics on the thing. It was an absolute breeze!
Those tablet e-ink devices does some of that. reMarkable is just a notepad with very simple cloud sync to their cloud.
But still - the device is quite awesome and I tough myself some drawing. Use it all the time to prototype diagrams and show architecture. Love it that I can draw some weird system connections on a diagram, copy and paste, and change some parts. Then I send a PDF and use it as a flip-book on zoom cals :)
Opensource tweaks are pretty good now. Some are actually obsolete as ReMarkable did nice improvements to zoom and document links. But most tweaks support RM2 already.
At this point the only feature I'd say is lacking is some kind of e-book store integration. I'd like to be able to purchase books from mainstream publishers to read on the device (it's sad how few publishers distribute books in non-DRM, plain ePub files these days).