[ajju]

UberX is $1 more per mile than a taxi. Also, the minimum fare is $10 for UberX vs $3.50 for a cab.

Uber Taxi charges a fixed 20% tip and $1 booking fee.

Sources:

https://www.uber.com/cities/san-francisco

http://www.sfmta.com/cms/xcust/indxtxcust.htm