I had put in 1000 INR into OLA money and they have added the 1000 rs from their end as promised . This made my balance as 2000 INR.
I have used their service 3 times in total. Out of that I got 50% off in 2 times( when I called them to come back from Chennai central to Velachery) and 25% off in the other trip
The OLA money deducted for each of the 2 trips was around 160 / - INR against the normal auto charges of 200/- to 300/- INR . As I had got 1000 to 1000 offer, also, my net expense is actually 80/- per trip. This is unimaginably cost effective .
I have heard few stories from my friends of no shows of drivers especially night bookings. I think they are infant as of now in Chennai, at least, and hence request give more time for maturing.
Overall, my advice is to try them in day time and especially when you need cab from railway station and airports.