I am having the same number for more than 10 years, got it when it was hutch(vodafone), when porting became a reality I ported to BSNL, not satisfied with vodafone weak signals.
But soon BSNL was totally inaudible many times with your own echo, so ported to docomo, which gave initially good quality and cheap calls, but later signals became difficult to get and it had no 3G, so went for airtel considered best.
Thought the service was just above average cost was enormous, 3G speed was not as expected and the packs for post paid were tricky to customize to a person s needs.
Thoguth aircel will be good and ported to it, the worst network of the above, it was totally pathetic and waited for he 3 months for next porting and finally landed up with idea, when my friends suggested. Got a good postpaid pack with 500 calls, 300 sms, 750MB 3G data(beyond which unlimited 2G)per month at 399/- plus taxes. More than money the service is excellent with good speed and call quality.using it for past 10 months with no hassles or complaints. Negative things are non-existent customer care, when u need extra data enormous cost, and difficult to access monthly bills online