I bought the Remarkable 2 about two years ago, but since I had to get a replacement, I guess it counts. I love the e-paper's magical feeling in general. Remarkable in particular amazes me with the openness e.g. giving me SSH access to the Linux-based system. I wish they'd focus on customization, tinkering and stability, but unfortunately that doesn't seem to be the case.
It has a Linux-based OS that you can SSH. You can install community-maintained stuff with Toltec. The Awesome Remarkable is a great overview.
However for 3rd-Party software and more general features, even with the openness, it doesn't come close to Onyx. In general, the remarkable is more focused on distraction-free e-reader and note-taking capabilities. And honestly even being part of this target audience, if it wasn't for the affordable replacement offer, I probably would've rather looked into other e-ink devices.
I was thinking about purchasing a remarkable 2 or a Boox Note Air 4C before but in the end I would have to tinker with all of them to get a setup that meets my needs so I just went with the most open variant.
I hope the hardware is up to the task but just reading through the specs it seems pretty similar to the remarkable 2.
Out of interest, what happened to your first remarkable 2 that you had to replace it?
It took a bath in ice tea for a few hours and it suffered even more when I stupidly connected it to the PC before I saw the wet folio and bag. I probably would've looked into other alternatives, too, if I didn't receive a replacement offer for ~130€. I love it, but it does have many faults, that for some people may be unacceptable for the price. But that seems to be the current state of e-ink tech in general.
For 130€ I would have taken the remarkable 2 as well, unfortunately used offers start at 350€ here. As for new, the PineNote is actually cheaper than the remarkable 2.