I disagree. I have used both d2h and TS for long time and on same Sony TV. D2H HD Channels are pixelated by a lot. That dth has no quality at all.
Cheap hardware might be cause of d2h pixellation. The same grade hardware they are still providing, so no idea how you are getting best quality picture now!
Coming to topic, i feel its that type box model issue.. @Siva bro, If you can request them for a HD PVR box to test the picture quality on your TV.. Give it a try. To check if pq improves, hopefully you will get a noticeable difference.