The best thing about zotero is that becuase it is open source, you xan customize it a lot. You can even add sci-hub addon that lets you get the pdf from sci-hub for non open source sources. So if I 'm interested in a paper for reading, citation or anytjing else I just add it using one click (using browser extension) then it is ready for reading. I can do bibrex (using the addon). I can use zotfile which give much functionality, I add iPAD sync and highlight the paper and then extract that to zotero.

Sci-hub addon of course ia not even listed or recommended by zorero community (for obvious reasons) but this mix is very good punishment for elsevier for all the horrible things they do to science. And how even their Mandeley is evil now.