Ola may work when you want to use it like an auto i.e. walk up and get a cab, however, it does not work like a regular reliable cab service. I booked the prime service and it was confirmed, 30 minutes prior to that we get assigned a Tata Indica. I call up the customer service number and they say that system assigned the car automatically as there is no prime cab available and there is nothing else which they can do.
I go online to Meru, book the cab and the guy shows up in 15 minutes. This they did for a commute to International Airport where the bill would have been a pretty high number. So, I will personally stick by Meru for my airport bookings as I have been doing for the last 8 odd years.