I used to get a FastPass every month and ride Muni whenever I could. I stopped doing that when they raised the price to $55. That's too much simply for the convenience of the pass and only makes sense if I'm going to use Muni enough to actually save--which is unlikely.
Much as I hate it, I've actually contemplated joining the large numbers who do it and simply boarding through the rear door without paying until Muni comes to its senses and stops raising fares for the diminishing number who pay while tolerating so many who don't.