I've been using Tata Docomo SIM as my primary SIM as it definitely has low call rates.
But one thing that disappoints me is the slow internet speed. It has only 2G speed in my area. It's way too much slow.
Whenever I go to kalyan-badlapur area it gives 3G spped.
But where I live, there is just 2G speed which is just slow like a speed of turtle.
I would recommend everyone Vodafone or Jio for good internet speed.