Ola is the first online cab service I heard about. One day I was late for my train I was waiting for the bus to station. There was no any bus for station that time. Then I booked a cab from ola app. Cab came on time, service was good and it drop me to the station on time.
After that I used ola many times and the best thing is that there is no any charge for booking cancallation, if need due to some reasons.