Ask HN: As of 2017 – best PDF/academic paper reader?

I guess its a sad state of affairs that the landscape has changed so much over past few years, but wondering what people were using to read/organize academic papers, i.e. from PubMed or ArXiv?

Mendeley - still developed, owned by Elsevier ReadCube? Papers (acquired by ReadCube...in limbo) DevonThink? iBooks? Zotero? flat files? Appears Sente is sunsetted..