Zotero is my primary reference keeping system. As a research group/company we switched from bibtex to zotero because it allows to put the PDFs also into the collection and has web based browsing included without custom software.

However, the interop with bibtex could be much more seamless. The zotero db feels a bit like a silo, which is sad. Thankfully it is open source so somebody (including me) could improve this in the future.