I can’t find a thread laying out the advantages of EndNote over its major competitors, like Papers2 or Sente. Are there any? Could someone please lay out the pros and cons or just point me to what I am sure are copious discussions of this in the past?
You can find a comparison of most bibliographic software in Wikipedia http://en.wikipedia.org/wiki/Comparison_of_reference_management_software, though I note it only has Papers, not Papers2 listed so may not be current.
If you conduct a search (e.g. google) on EndNote and Papers2, you can find a number of posts announcing the features of Papers2 with its limitations discussed in the comments below the post. For example: Item1, Item2, Item 3 (in the third item, an EndNote user converts to Papers and comes back to EndNote).
No doubt you can do the same for Sente.
Hope this helps.