I have my printer set to scan and save the files to a NFS. Paperless-NGX picks it from there, does OCR and saves it. I guess I could just leave it on the NFS, but I do like the UI of P-NGX.
I got a Brother ADS-4300N to use with p-ngx, works very well and also is way faster than the usual document scanners on MF printers (duplex is done in one pass, for example)...
set up was straightforward and the functionality is great