@kdfrawg The latest version of Sierra has supposedly rectified the previous version's tendency to strip annotations from PDFs after they were shared electronically. Example : every two months I compile a crossword for the Mac User Group magazine Then I send the answers & a partially-filled out grid to the editor for inclusion in the next monthly magazine. When I was on 10.12.3, no matter what I did with annotated PDFs, they were absent when the editor opened the document.
Otherwise I agree with the "unsung hero" status of Preview.
// @streakmachine @gtwilson