I live in a area where Ola has not yet added their Cabs.
But whenever I go to cities like Hyderabad, Chennai I prefer to use them.
I like their service. The reason they are the leading cabs is they keep upto the mark.
They reach to your hotel/house within 10-15 mins.
They have the GPRS tracking which enables to track where the cab is.
They keep their cabs clean.
It also enables to choose the type of cab.
And for the best part they are extremely cheap!
"Keep up your standars OLA":-D