Earlier I used tata sky but now am using normal cable service. when it was recently launched, what attracted me was its unique new features, which no cable provider used to provide like
live tv pause
recording
games
interactive interface which included various categories for channels
pay as you use i.e. pay for channels which you use, based on packs you select.
the problem with tata sky was that, during rains, it used to interrupt a lot, there was a day when it stopped for around 4 hrs. but maybe now, since it has been many years the service would have been improved.
another reason for not using tata sky was that the packs which I wanted were too costly. and the cable service had almost all channels I needed.
picture & sound quality is great. normal channel feels bit like hd but surely far better than cable. also when I installed new, it took lot of time for my account to activate.
finally I would say, if you are looking for new unique features and good picture quality you should go for this. but pricing is bit high. also I am not sure that service & support has improved or not.