Adding to my post, there is a long discussion relating to this issue entitled:
The bottom line seems to be that there is a bug (or new feature) in Safari 7.0 such that one is unable to set the browser to automatically download pdf files on which one simply clicks.
Using the terminal commands above one can now turn on and off Safari's ability to display pdfs, which is a pretty worthless option.
I don't have any of the Adobe or other plugins to confuse the issue. The behavior is stable and reproducible.