I am using mobile phone since from 2006, First sim I bought was TATA Indicom but after few years I think approx 3-4 I ported my SIM to Vodafone and today this sim is my oldest sim and widely distributed.
Vodafone is a superb network. Spread all around. Its 3g/4g network is awesome even 2g performance is much better than other networks.
Customer service is very good they never disturb you without any genuine reason and they are very supportive.
Charges and Billing are approx same like other brands but its connectivity and speed is much better than else. Vodafone is a good competitor from JIO dominated Telecom war.
So if your going to buy a new sim buy VODAFONE.