I've only used the Boox Tab Ultra C Pro and Remarkable Paper Pro but the latter is definitely a lot more "calm" than the former. I primarily use it only as a note-taking device. YMMV but for me, while the former had a full-fledged Android and the associated bells and whistles like the corresponding apps, local AI features, handwriting search and so on, the RMPP nailed the few things it did. Its sync was pretty slow and it needed wifi for any of the handwriting conversion but its latency felt a lot better (albeit the redraw was a bit annoying) and more importantly, it really felt like they nailed the colors better. When I use red and blue in the RMPP, I can easily recognize the diff without straining my eyes which was not the case for me with the BTUCP (is this the correct short form?).

The keyboard folio was also better for the RMPP since I often experienced loose contact with the one on the BTUCP when I used it on my lap (flat surfaces were good once I set it up). Otoh, the material used in the BTUCP was much better since the RMPP one uses a polyster weave which often leaves me with slight goosebumps. Additionally, the keyboard folio isn't a feature I use often.

I really can't talk about the others so for all I know, Scribe or supernote might be a lot better. RMPP does have a 90 days no questions asked return policy if you want to try it out (though I'm not sure how much that's worth).