Sente's 5.4 upgrade takes it from amazing to phenomenal.

This program (in version 4.x, if I recall) single-handedly converted me to a Mac. Nothing manages your searches, keeps you up to date on the literature, organizes your pdfs and other documents, AND functions as your citation manager. Sente does all that, and with the 5.4 upgrade you can now do your search, select a reference delivered by PubMed, and with one click, there's your imported, renamed, stored pdf. Sometimes you have to click twice. (If you're old enough to remember going to the library to photocopy an article, clicking twice is okay. Even if you're not that old, clicking twice is okay.)

Just so you know going in, it's still only amazing if you work mostly in WoS; it's phenomenal properties are for PubMed. But "amazing" is still pretty good. I.e. on WoS you still have to go download the pdf through your own search, and then drag it onto the reference in your library to be automatically renamed, organized, and linked to the reference.

This new release gives Sente many of the features that Papers has and Sente didn't. (Papers doesn't do the citation manager part, but it has some cool tricks that might have tempted you away from Sente. Now Sente has those cool tricks too.)

It can sometimes be a little rough around the edges (I can't get the references to behave as reliably as in RefMan or EndNote), but the other features are so mind-bogglingly useful and easy that I don't mind doing a bit of tidying up.