I'm looking for a software to manage my readings. The books that I read are mostly scientific literature, so I'm annotating them quite a bit (marking text, adding notes to a mark, adding free-flying notes etc.).
I would like to have my notes with me, no matter the device I'm on (laptop/tablet/smartphone), so there would have to be some kind of synchronisation, when a file changes (because of an added annotation or because I added a new file). I mostly live in the Apple ecosystem, so I would require a MacOS/ iOS application. But a recommendation for other platforms would also be highly appreciated.
I have already considered the Adobe Document Cloud, however the files would always be on a server, which delays access to the documents (they have to be downloaded to be accessible). The main cloud-providers all have their desktop clients (Dropbox, Google Drive, One Note...), but unfortunately they only work in a desktop environment. I haven't found an auto-syncing application for mobile devices yet.
A paid application or subscription-based plan would also work for me.