I was an Orange subscriber, when I was in Mumbai for a duration of 2 years. It has exceptional network and worked almost without fault.
I personally went to Orange Showroom to get the new postpaid connection. It took not more than two hours to get my new connection activated. The staff is high on alert, understanding and helpful. They gave me a crystal clear understanding of the product they were offereing and the options which were available at that time.
For the matter of fact, they even told me that they will charge one months rental in advance (a fact hidden by rest of the providers). Their bills are simple and understanding.
One I altered my plan, so I got a call from orange executive confirming me about the changes. I always used to get a call from the orange staff intimating me about the changes in the services/tariff/plans.
The call center representatives were always helpful.
In case of termination of the service (as I was moving out of city), it went completely hassel free.