I started using Zotero a few months ago when a major Firefox update rendered the Scrapbook extension non-functional. It's nice to be able to take quick snapshots from Chrome or Firefox and save them to the local document repository. I found this guide helpful in getting things set up:
For the cloud side, there was a nice tool for linking a Google Drive full of PDFs with entries in your Zotero database, bypassing the cloud storage limits.
https://github.com/mtekman/ZoteroGoogleDrive-PDFLinker-Cloud