Dont be deceived by their nice attractive website.
Here is what happened with me:
On a Thursday night, I booked a cab for 6:05 AM on the following day. The call center guy responded very positively and confirmed my booking. Just as it happens with every cab service, I was expecting that the driver would call me to confirm the address. I didnt receive any call till 6:00 AM. So I called back the call center. I could identify that the same guy who responded previous night is responding again. He was able to recollect my address just with my name (This could be because I was the only one who booked a cab with them). He said that he will check with the driver and call me back. Then he never calls back. I call him multiple times and he doesnt pick up the phone.
The whole drama was freaking me out as I was running out of time to catch my flight. It was already too late to call any other service. So I ran out to see if I can get something. After running for over 1/2 km, I found an auto. Just then the silicon cab driver calls me. Clearly, he was just out of his sleep. His voice suggested that he was still in the hangover of last night. I realized that it would take a while for him to reach my place. So I told him to come to a point where he would be able to reach quickly. I went there by the auto. After a painful (because of shortage of time) wait for 10 mins, the wonderful cab finally arrives.
Its an Indica in throw-away condition. I opted for non-AC as it was early morning and it cost just 700. But I didnt imagine an airport cab to be in such a worse condition. The driver seemed more like a truck driver from rural Orissa. The whole cab was stinking and I didnt want to sit beside that driver. So I chose the back seat. Though the person was not punctual, I must say he was considerate about me reaching on time. Unlike what I feared, his driving skills were good. Inspite of his sleepy eyes and hangover face, he managed to drive the cab at its top speed (may be 70).
Finally my flight got delayed by half-an-hour and I happened to reach on time. The driver asked me for toll-fee but I gave him just the 700 which was promised. I should have cut the 50 bucks which I paid for auto but couldnt do that looking at the sad face of the driver.
Bottom line: Go for it only if you are too much considered about the 200 or 300 bucks you may save with this and willing to take the risk of missing your flight or have a backup option