I have taken lot of rides with Ola for last couple of years and never had any problem with my rides that I can recollect. It always shows the estimated price to reach the destination and that is what I have always paid - not a penny more or less.
More recently I shared a ride with 2 other passengers from South Delhi to Dwarka, New Delhi. I booked the cab using my broadband WiFi at my place and went out as the arrival showed 7 minutes. Since I didn’t have net balance on my phone, I took the screen shot to remember OTP and vehicle number. I waited at the pick up location and didn’t even bother to call the driver. But after 5 minutes the cab arrived at my location. I double checked the vehicle number and halted it. After punching in my OTP we headed for our destinations. The drive was smooth and on time as the traffic was less at that hour. The driver was professional and kept to himself less we asked him for some information. Once the destination was reached he rendered the exact change as I paid him by cash.
Unlike Uber drivers who I had had bad experience with before, I never faced any issues with Ola drivers, vehicle conditions, punctuality, et al; though the charge may be a tad more than Uber pool than Ola share ride.