http://h2zkj5xeycxb2esnyqeabuuo6ui6jlkdb72qjfi2hu3y3h5ilpmjphid.onion/wiki/Arrival/index.html
This is slower (an hour to the centre rather than 25 minutes), less easy to use (you can just take the shuttle bus to its terminus, and it has announcements about the stops along the way), stops running at night, and you need the exact money to buy a ticket. On the other hand, it is cheaper (£1 for a single ticket), and goes along Forrest Road, which is almost as near Teviot as a taxi would take you.