I already had a licence of Endnote X2 on my computer, mostly to insert citations in word. In my opinion, Endnote is not a good software: it’s slow, heavy and not appropriate to manage your bibliography. Indeed, you cannot create sub-groups in your custom groups, associate keywords, use smart folders (maybe people from thomson don’t use mac?), etc, etc… But, it’s the only one that propose a decent integration in word to insert citations. BTW, you should note that you always have to upgrade to the new version if you update your microsoft software (nice, isn’t it ?). No CWYW update is offered for older versions of endnote if you buy the office 2011 (and, right now, endnote X4 still doesn’t support office 2011, very nice, as I said…).
So, I had recently bought a licence for Papers for my macbook to manage my bibliography. And you can trust me, this program is awesome!!! First, the import of PDF files (great feature) works perfectly fine. If Papers cannot recognize your PDF file, you can identify the article by querying different websites. In many cases, it works. And, if not, you can select a part of your PDF and use your selection to query databases (and then, it always works!). You have a full-screen mode to read PDF, annotate the articles, create as many groups and sub-groups you want, create smart folders, search through your collection is spotlight-like, and this program is fast, really. What is missing? In my opinion, an integration with word. I sent mails to the support, they told me that this feature is planned (but when?). But, this is not the first purpose of this software: it was designed to manage your bibliography, and, it achieves this task perfectly! You should definitely give a try to Papers. The pricing policy is quite nice: 40% off for students, and only 34 € ($40) for the others (compare to the price of endnote X4: at least $249, and no student pricing).