I have been an enthusiastic Papers user since 2007, when it had truly revolutionized pdf desktop organization and bibliography management.
So I had indeed high expectations on Papers 2 which has been punctually released today.
As Papers 1, the new application from Mekentosj runs smoothly and offers clear and immediate tools to organize articles and other media.
Papers for IOS. There is an iPhone / iPad app that is able to sync to Papers2 desktop but it will cost you €11.99 / $14.99. At this time I have chosen to drag my Papers2 library in my Dropbox account: in this way I can have access to my pdfs on other computers. It's a DIY-multiplatform solution I have figured out.
Other than pdf. Yes, but at the moment I prefer to use web tools such as Evernote to manage files other than pdf from my scientific library. Papers2 offers a browser bookmarklet that will open a web page directly in the application: this is an excellent crosstalk tool, but, as I said, at the moment I wouldn't organize bookmarked web pages in Papers2, especially because it doesn't snapshot but just links to the page, if I got it right.
Magic Manuscripts. Is a menu toolbar app that can be running even if Papers2 is closed. It makes you search through your library of papers and gives you the citation which you can paste, for example, in other applications. A very handy and time-efficient tool!
Livfe. The disappointing surprise: it's not ready yet! This was the (social) feature I was waiting for the most.
