Pros:

• The biggest advantage is HDMI output, while Tata Sky doesn't have that option. HDMI output gives better quality, at least for me connecting to my LCD monitor directly, instead of any tuner card.
• Universal Remote, I don't know how much that matters to you, but anything plus is always better.
• Very good picture quality, audio can still be improved, as audio doesn't give the stereo sound feeling. I think the picture quality is almost the same as others, or slightly better. But don't go on stupid claims like MPEG4 improves picture quality or Reliance have 5 times better quality. As MPEG4 doesn't have to do anything with picture quality and Reliance have only 1 HD channel, Nat Geo. The rest channels are comparable to Tata Sky DVD quality. Also note that the Reliance HD is 1080i and not 1080p.
• I think Reliance plans are cheaper, especially when you want all the channels. Like you want HBO, your wife wants Colors, kids want Pogo, sports channels, etc. Tata sky and Airtel costs much more if you want the maximum channels.
• More hard disk space, for 200 hours recording. Again anything plus is always welcome.
• Reliance is known for blowing away competition, so you can always expect new features and packages from them.

Cons:

• Most of the internet review sites will tell you, that the big Reliance logo is the biggest con, they all tell lies, and are paid reviews. The logo should be small, but it's ok, as there are many major cons.
• The biggest issue is the box and its software, which reliance claims to be state of art, with great features like mini guide, etc. But in reality the software sucks, hangs a lot, can't record simultaneously while watching other channel and not hanging. The software is still incomplete like the Select options doesn't change category, their is no reminder feature in HD DVR. Recording on power resume should be there. Changing channels is very very slow. Voice comes after 15 seconds, while jumping some recorded programs or channels. By the time, mini guide gets program information, timeout occurs and guide goes off the screen, and you have to start again. There is no sleep mode, and sometimes it start automatically (Yes, it does, suddenly TV appears while I am working on computer, as both are connected to same LCD, even when I had switched off DVR from remote).
• Service quality is low, and the signals are lost often.
• For Reliance customer care, pathetic is too small word for them, highly inexperienced staff. You will be put on hold for ever. They don't know anything, about new features, you have to pay before trying, and paying by check takes 5 days, if you want new connection, while Tata Sky gives you instant connection. Tata Sky is "5 times better quality" in terms of customer support.

Conclusion:

While there are many negatives, especially the software, but the good picture quality combined with attractive package price is enough to attract anyone. I can definitely recommend Reliance Big TV.