I have been using indigo airlines for my air travels for around 3 years now. I normally fly from Mumbai to my hometown. I have never faced any major flight delays or cancellations so far. The check-in process is also very smooth. The flight attendants are helpful though sometimes come across as a little aloof. But nothing serious. The prices are very competitive and if you book before a month then you can get a ticket at a decent price. I have used their tele booking facility once and it was fine.the takeoffs and landings are ok but can improve a little. I would recommend not to seat adjacent to the turbines as the noise is irritating.
Overall a good airline to travel in.