I had to use a trial version of Endnote 9 because a collaborator was using it. It was slow. Adding paper by DOI would freeze the interface for ten or more secon

I had to use a trial version of Endnote 9 because a collaborator was using it. It was slow. Adding paper by DOI would freeze the interface for ten or more seconds on a database of less than 100 papers. Meanwhile adding a paper by DOI to my Zotero DB (curently 2000+ papers) is a snap.