If app-fication of ride hailing is what you want, it's worth mentioning that in the SF bay area, Flywheel has done an excellent job of making a feature-rich app and network [0]. Personally, I have found it to be an excellent service, the things that matter the most to me are availability of rides, timeliness of driver dispatch and arrival, and communication with drivers (when necessary).

[0] http://www.flywheel.com/passenger-app