Have been using VODAFONE as my primary number for over 5 years till now and thankfully I have not faced any problem yet.
I was really happy when they slashed their internet rates just like jio and have plan for free calling as I had apple phone and only one sim could be used and I could not use jio.
I really like the internet speed of the VODAFONE I even use the internet through hotspot on my laptop and I dont feel like the need of getting a router. I got a JIO FI but vodafone internet speed is better than it.
I even have my office in basement where most SIMs go dead but I can receive call on vodafone that is the best part of it.
I have never been charged unnecessarily which is their best thing, I have opted for 3 gb daily plan and I am really happy with the speed throughout the day and also at places where I go.
Sometimes at some places it does shows network issues but overall the networks are wonderful
I will continue to use same sim for as long as possible