I'm using Idea and Vodafone. Both are still different only. Idea is doing all process so fast. Idea now uses Vodafone towers just like before but without charges. That is I had to pay when I use Internet in 3g as I have only 2g/4g Internet. Now it's free. Vodafone on the other hand still uses its own network. Vodafone still doesn't work where Idea works better.
I'm waiting for Vodafone to complete this merger process but they are very slow.