I have travelled on Air Deccan for atleast 10 times now; on different routes. I have also used another LCCs like Go Air and Spicejet sometimes but Air Deccan is definitely THE best LCC operating in India. Read why:
Bookings: Airdeccan website is realyy fast and very easy to navigate. Plus they have an efficient 24 hour call center backup if you face any problems with bookings.
Prices: Air Deccan always give you the lowest prices and the best timings. Note this: Which LCC offers you a Mumbai-Delhi ticket at INR 2199 for the flight time 8.25AM-10.25 AM?
Punctuality: Only once I have found Air Deccan to be delayed; that too was for 45 minutes only and I was informed well in advance
Flights: Now a days, its operating all major routes using the brand new Airbus planes. They are MUCH better and spacious and less noisy.
In-flight Services: They offer you free water these days. And sell food items. Tried their sandwich, at Rs. 30, its a pretty reasonable and good option. All food items are priced very comfortably.