I just use both pen and paper & Simplenote and connect it to apps like Nv etc. It's free (for now), open source (mostly?) and lets me sync across desktop/laptop

I just use both pen and paper & Simplenote and connect it to apps like Nv etc. It's free (for now), open source (mostly?) and lets me sync across desktop/laptop/mobile. Also has a nice export tool which I can use should I need to migrate. One downside is markdown is not supported on the mac version from some reason (works on windows/mobile)