In terms of overall picture quality, tataplay is best , then comes airtel .one can consider tataplay if zabardast hd pack is available all over India else blindly go for airtel (basic hd pack + channels you watch as add on)
Hands down Airtel. It is the only DTH provider with 30 days lock-in period so you don't have to waste your time adding and dropping channel. You can peacefully watch your favourite channel for full 30 days without any inconveniences.