[arm]

El Capitan is probably the best choice at this time; Sierra is an absolute train wreck:

http://tidbits.com/article/16966

EDIT: 10.12.3 doesn’t seem to be much better, sadly:

http://tidbits.com/article/17010

[kalleboo]

Sounds like it's only an "absolute train wreck" if your workflow depends on editing PDFs with annotation layers in software that uses PDFKit.

My interaction with PDFs starts with viewing a linked one in Safari and ends with "save as PDF to web receipts folder" and for that kind of usage there are absolutely no problems. I always thought that for anything half-advanced with PDFs (like filling out forms) you'd want to install Acrobat Reader anyway...

[photojosh]

Filling out PDF forms is a pretty normal consumer task these days, I wouldn't call it even half-advanced.