After reading the reviews I feel there is no clear winner in this part of the market.I have (with a lot of hope) opted for Dish for my new Sony bravia hoping I will be able to do recording on USB (which tata sky charges 6k for the box)..dish gives it for 2900k.(but you can not watch any other channel while recording is on, esle it would stop recording).dish also promised 40+ HD channels which is not the case with tata sky(they have 10) but tata claims they have true HD whereas dish has HD clarity.
So finally, it boils down to how much of a power user you are..how much of time you spend watching TV..
Important things to look at
Customer care
Number of Channels offered/monthly recharge
Ease of use
Migration ease..from HD to HD+ etc
Bottomline is every provider has some pros and cons. Act as per your wisdom and local opinions.