I have been a subscriber in India for about 4 years now. It started really cheap at 500 bucks/annum. I thought it was a steal at that price, next year they increased it to 750 odd. 3rd year it was upto 999/annum. I still felt it was value for money at that price. This year they have jacked up the prices to 1800/annum which is ridiculously high.
In the last year they have hardly added any substantial channels and its still pretty much the same set of channels since the first year (Jhankaar Beats, Orbit Rock, Bob are the channels I listen to largely and my parents listen to Farishtaa). Its pretty much the same set of channels with not much variety added.
So I am not sure how they keep increasing the prices. At 1800/Annum, its almost close to your cable prices! So unless you listen to radio as much as watch TV, it may not be value for money.
Keep this in mind while buying WOrldspace. You have to shell out 1800/Annum (at current prices) every year else the Worldspace unit is as good as junk. I am thinking of using the money to buy an IPOD instead rather than renew my subscription.