Hi, I’ve been using Mendeley a good bit recently for reading and have made use of the import pdf option often (partly because Mendeley is not set up as thoroughly as EndNote for export from many databases). I’ve seen in these cases that I often have to check and correct reference data and it has been helpful to be able to see the full text article and the reference data at the same time in the program window (in the desktop client). New RefWorks also allows this. Being able to see the full text and to see and edit the reference data would be nice.
Being able to see notes would also be nice. Mendeley desktop also puts pdf annotations in the notes tab, also nice. It’s nice to be able to move through articles viewing one’s notes just by clicking arrow to next article (or however the next article is selected).
It’s difficult to like Mendeley for reading but to prefer EndNote for citing 
Have a nice day
John