I am using Videocon D2h since last 3 years. Planning to upgrade to HD set top box, I found that there is one one HD pack available in Bangalore for INR 650 per month, which is very costly. Compared to this, Tata Sky has far more range of HD packages relevant of personal choice and liking, that costs cheaper than Videocon D2h.
Apart from that, I felt Videocon d2h service is very good and disruptions are rare.
Picture clarity is good. But Tata Sky provides better sound quality along with picture quality.