Readeck (
https://readeck.org) could be an interesting alternative.
I've tested it (self-hosting is the only solution currently offered, but a hosted service will be available soon). It's easy to save content with a browser extension. For the moment, there's no app for mobile devices yet, but there's a workaround.
For now, Readeck allows you to export articles and collections as a single ebook.
We still need to find a quick solution to transfer ebooks to Kobo, as was possible with Pocket, without any hassle. (For now, I'm adding calibre-web and synchronizing with Kobo Sync.)