ERNIE BEAL  Can't wait to see which one (Sente or Bookends) ends up implementing direct support for OpenOffice 3.x.   
(Version 5.6.13)

ZEBA  One more thing... this is the price for 3 licenses. I need only one license for most of my programs, as most of other users (students) do, but developer is not willing to offer that in their business model.  
(Version 5.6.16)

ALANTERRA  I have used Sente 5 for almost a year now, and am just upgrading to Sente 6.

Pros--powerful management of references for reading, browsing, filing, and including in bibliographies. Able to take large databases in a single bound! Great support for downloading papers from the web. All-in-one solution for management of references, including web references, journal papers, books, scans of xeroxes. And now including synchronization of libraries between computers.

Cons--occasional user interface glitches, undo not fully implemented, no comprehensive user manual.

While I still have not used all the parts of Sente, it has changed my life researching various topics. I right now have 3,000+ references, and this is growing quickly. My research is in various old corners of the biological world, so I can't use PubMed, and Sente's integration with Google Scholar is great. (In spite of all the data problems in Google Scholar). I often am using old journals, and I xerox the articles and scan them, and it is easy to add these to Sente. Integration with JSTOR is great.

Sente 6 now has "keywords" and "tags", keywords being supplied by the author and skimmed from the journal's online site, and tags being supplied by the user. Not the most obvious solution, but I think it is pretty common. You see the same solution in Papers.

I am not using the synchronize feature, but the word is that it works well, but causes some limits on how other programs can link with saved pdfs (because Sente needs to copy, rename and delete pdfs behind the scenes to implement synchronization).

I just spent a few hours looking at some of the competition, and here are some comments:

Papers: Nice but incomplete. For instance, you can't add books to the reference database. And, while you can add tags to references, you can't add the same tag to multiple references at a time. Reading their forums, it is obvious that many people want these features, but the authors have not had time to implement them yet.

Papers focuses on reading pdfs, not compiling and filing them. While it is useful, it might be just as useful to use the Finder + a good pdf reader like Skim.

Mendeley: I couldn't transfer my Sente database to Mendeley--the pdfs did not transfer (meaning that I would have to drag and drop 2,000+ pdfs one by one). Other fields that I use in Sente to organize my database (like Status, or Library Call #) also didn't transfer. It seemed like a better solution for a lab that is working mostly with recent documents, not a person who still uses a physical library like me. Mendeley is still in beta, but the price can't be beat (free), and Mendeley is cross-platform.

For me, the time I have saved keeping my references organized in Sente is more than repaid by the cost.  
(Version 6.0.19)

EMCHATEAU  For me also the best i've tried (and i've tried almost all of them). Because of the mac interface, it's a really easy soft for mac users. But it is also very powerfull and truly manageable.

I really enjoy the keywords system and the smarts collections. PDF meta data are easy to receive and it makes it really easy to add a new ref from the pdf on your computers.

Compared to Zotero, it's really more powerfull and easy to use but it doesn't have the export of library on the web and share collection that zotero gives.

Anyway the data are exportable in different formats so you can go from one system to anotherone witch makes your data really safe.

I regret it doesn't support different language for the date citation as i'm french. But i hope they'll change this very soon.

As i'm an historian, i also miss the circa citation in the date field.

Even of that, i'm still using it, because it's so great !  
(Version 5.7.5)

ALANTERRA  I haven't explored all the features of Sente, but it seems to be head and shoulders above its competition. I spent the last few days looking at Sente, Papers, Zotero, and one programs that I didn't even bother to look at due to bad reviews (EndNote).

For my needs, Sente is the best. I am trying to organize a couple of thousand pdfs (and a few other kinds of documents), and continue to research various areas from that base. Sente seems to have a strong emphasis on medical research (it uses PubMed as a default database to look for things, and I haven't figured out how to change that). But the tools of being able to look up bibliographic data automatically in Google Scholar, use keywords, and browse pdfs from within the program make the program exactly what I need.

As of Feb 2009, the developers are giving some insight into the next version of the program, which looks to be a useful improvement. It will be a free upgrade to anyone who purchases the program after Jan 1, 2009.  
(Version 5.7.3)

ASDFASD  It aims to be used in academia, but at US $89.95 it's to expensive to be used by students!

So two thumbs down.  
(Version 5.6.13)

LEV  Gosh, Sente and its competition Bookends don't need reviewers; at the moment, they need a sports commentator. Sente just pulled into the lead with totally customisable conditional fields ("print X unless field A is empty, in which case print Y"). Can't wait to see Bookends' response. Except perhaps I should do some work, instead of watching Sonny Software and Third Street doing *their* work...)  
(Version 5.6.4)

LEV  For those of us in the (non-MLA) humanities, life just got a bit more difficult.

With Sente’s latest iteration, we now have two first-rate reference managers (Bookends being the other) and no excuse for sticking with the lamentable gouging corporatism behind EndNote ($100 a year, more or less, for “upgrades” which consist of bug fixes (more or less)).

Sente now offers “tabbed browsing” -- an onboard WebKit browser with “data detectors” that enable you to home in on, for example, a JSTOR paper and grab its reference and PDF. It has great note-taking capabilities, RTF file attachments viewable from within the app., easily-customisable references for footnotes and in-text styles, and an excellent UI.

The choice is hard.

Bookends is probably a gnat’s-whisker more customisable on the citations front (particularly with its ability to force, to some extent, the behaviour of a citation when an element is missing) and allows the user to rename the same field for different reference types (“Book title” in Books, the same field called “Article title” in Journal Articles, for example). Sente is a bit more authoritarian in this respect.

For online searching and grabbing of references, Sente has the lead. Neither of them has two great killer features -- the ability to copy a note or a quote and have it appear in the target document complete with reference and pages cites, and the ability to link references/notes/quotes to other references with some cognitive functionality, as in the great and lamented Papyrus which never made it to OS X.

(In Papyrus you could link My Great Book to His Lousy Book with the link “Cites” and lo!, His Lousy Book would be linked to My Great Book with the link type “Cited in”. Marvellous).

But I imagine these things will come. The Sente guys and Jon of Sonny Software, author of Bookends, are now engaged in an excellent battle for mastery and for once the end-user is really benefitting from competition. Hooray!

The only thing I can say is: try them out and decide for yourself. But for heaven’s sake, do *decide*. Do *not* follow my example and end up with a Bookends database and a Sente database and *no real clue what’s where*. The end decision will be down, as always, to personal choice. But it’s really good to have such a difficult choice to make.

Kudos (kudoides?) all round.  
(Version 5.6.1)

KEYBOARDPOUNDER  THE best research application around.

I have tried them all, and Sente is amazing.

The interface: like a Mac, so easy.

Tools: all the features you will ever need.

Get it and compare, that's all I can say.

My hat's off to Third Street Software, you've made a true fan out of me.  
(Version 5.7.5)

JUST A USER  I like it, took some time ti figure out how to use it, but it has all the features I need and it works great.  
(Version 5.7.5)