These dumb threads cost money. 
I’m finishing up my masters now, looking into maybe going for PhD. Recently started using Readcube Papers but now I’m wondering about the Highlights app. Papers is clunky-looking but includes a library and research tools and seems to have a solid group of developers and user base, so I’m still leaning toward that option. Highlights has a beautiful interface but I’m not sure if it works well for BOTH annotation AND finding additional articles/sources (correct me if I’m wrong, please!). Looks like maybe Highlights stores its information as metadata? Still playing with it.
I used to use Zotero all the time but Papers imported all my Zotero library references, so I’m thinking that might do the job just as well. Has anyone moved away from Papers because of some compelling reasons I might have missed? Really trying to narrow down my toolbox, but threads like this make me wonder about the best option before getting too invested.