It is slow, and full of bugs. It used to bes to that pfs could be imported / added when viewed in Firefox, this is no longer the case, and the plugin wont even open. It is not possible to close the popup after on completes adding a site or reference. You have to close the pane all together, and then reopen if youre not done. Somehow, it seems Mendeley gets more buggy, and overall quality deteriorates with every update. I will surely look into your competition as this wastes to much of my time and focus!

I can import references but never the pdf. Almost useless

doesn't import docs.