I hope the reason they took so long is that they were waiting on a really good color e-ink screen, but I doubt it. That said, I love my Kobo Sage and my LazyLibrarian + Calibre-web + Kobo Sync workflow, and if you can do the same on these, then they'll probably be a good buy.
I can, but I'm not happy with it. If you containerize this setup, each container needs it's own Calibre instance and it's very inefficient. I run it on Proxmox and plan to either package it all in a single Docker image or roll it into my Ansible playbook on a different VM.