I have used their services in Delhi as well as Bangalore. Both were great experiences. I got the driver details promptly. The cab guy was on time. Was well behaved. Did not drive rash. Took the most optimal route. All in all a great experience :)
The only issue is low availability of cabs which is why not a very dependable last minute option. However for well planned travel its a great option.
Would definitely try their services again.