I used to be a Vodafone user for quite a long time but the terrible service of Vodafone made me to port my sim to Airtel.
But I am really much impressed with the service I got here!
It is enough to let me surf the internet quite seamlessly and Youtube videos can be easily streamed online by Airtel 4G internet .
Pubg(the popular online game) also gives nice ping and lets me play the game very smoothly .
At some times my internet speeds cross 35-40 mbps during daytime and over 55-60 mbps during midnight hours. Downloading speeds are pretty awesome too . Signals are strong in relatively remote areas as well .
The customer support is also pretty awesome because they respond fast to your complaints as well as sort out your problems much faster than customer support of other service providers .
In short, I would recommend you to shift to Airtel network especially if u live in northern part of Delhi .
Good luck!