Actually I flew out on a weekday morning (6-7am departure) and I personally waited only 5-10 minutes for security, as the employee by the TSA PreCheck sign motioned for me to join the line right then and there, so I didn't go back to the very end.

While long, the line moved briskly (multiple document checkers and X-rays in operation) so the maximum wait time from the very end would probably be 15-20 minutes, if that.

And I have to agree SFO is beautifully appointed