Replacing EndNote with Papers
I've been using combination of Scrivener/EndNote X5/MMD2Latex for a while. The main reason that I used Endnote instead of Papers was that I would share my libraries between My Macbook and Windows PC at my Office using Google drive/Dropbox. I needed a software that supported both platform. So I chose endnote over papers. Scrivener also has two version for windows and mac. So I put all my research file on google drive, so I can edit it on both computer. (Although at my university, the EndNote is not free! (65$ instead of >200$, but you need to get two different license, since the endnote's mac serial doesn't work on windows

).
It was a very functional workflow. I typed my papers in scrivener. Then I would compiled them to latex, I would export endnote collection to bibtex and finally, it would generate the bibliography. Also, scrivener supports endnote pretty well (Not as good as word, but it's OK).
Then after Papers for windows released, I was a bit hesitant to switch at first.
Now, I've switched to papers and I'm really happy. Mostly because papers directly supports and matches some of my favorite DBs such as IEEE and ACM. Whereas EndNote didn't support them (or I didn't know how).
The workflow is basically the same, I write in scrivener (most of the times between <!-- -->

), I use paper's \cite insertions, then I compile it to latex. And that's it. If I have to manually write extensive latex code (like for generating tikz figures, my favorite latex editor on mac is texnicle, then I use \input to put them back in scrivener)
BTW, my archive is ~1000 papers. I remember that the older version of papers had a huge performance issues even on this moderate-size archive, I think this was another reason why I chose EndNote back then. But now, Papers 2+ are handling it very well.
Also, Another important upgrade: SSD. Adding SSD drive can hugely improve performance of Papers or EndNote or any other app for that matter.
I also keep my papers-endnote libraries in sync just in case I want to turn back to endnote. I've not used end-note for a while. So I'm probably going to drop it.
Also, I never saw any reason to get the papers for ipad. I use good-reader for reading and it can open my google drive folders. In there, all of paper's archive is sorted by authors and years. So I can easily open & annotate those PDFs in ipad without any problem.
I'm quite new to using scrivener/papers/latex workflow. If someone has any suggestion to improve this workflow, I would gladly appreciate it.