If a pdf is saved with commenting rights enabled in Adobe Acrobat, markups are available with Adobe Reader.
But can you import the markups back as an overlay in your DWG, and track their status from within Autocad?
DWFs are easier to create, too, since Autodesk prefers them.
However, the big issue we've been running into is printing DWFs. We seem to have issue after issue, and problem after problem. Wipeouts print as big black blobs on printers that print PDFs just fine. The Print Dialog is difficult to control, and has this obnoxious tendency to want to throw pages on four sheets rather than print a 100% print on one sheet.
And the most recent issue I've run into: I used to use DWFs solely as a means to create PDFs. The only way I could get good PDFs was to print my drawings to DWF, then use the DWF viewer to print the DWF to PDF using AdobePDF. But now, I can't seem to do that in Design Review. Design Review seems incapable of noticing that my Adobe page size is 24x36, and keeps trying to reduce it to letter or ledger size.
We likey the red-line aspect, but we no-likey trying to print DWF files...