I use Mendeley instead of Zotero. I really wanted to like Zotero, since I hate Elseveir like the next guy, but Zotero didn't have any of the look-up features and ability to quickly import my papers (thousands). In Mendeley, I can just throw a physical folder into a folder and it'll tag and categorize the PDFs mostly correctly. I mean it is nice that Zotero has an import browser plugin (which, btw, Mendeley does as we…
Your information might be outdated -- In the latest version of Zotero, when you add a PDF to Zotero, it automatically retrieves the metadata via DOI lookup. (I don't think it would work with papers too old to have DOIs but haven't checked lately.)
The metadata retrieval process is a very handy feature, especially paired with Zotero's web browser plugin.
Zotero also keeps a repository of all the citation styles, which are curated and administered by the Zotero team and stored in a Github repo [2].