Zerodha is a nice discount trading platform.You can trade any stock F&O with RS 20.00 brokerage while in ICICI and Sharekhan you have to invest Rs 150.00 .So from this you can realize you can earn a good profit from it.
They have an excellent customer service .
you can trade through mobile app Kite.They have a back office service named Q, where you can see all your data.
They are very prompt towards your required actions.
But their mobile app crashes during big market fluctuations like Brexit, Demonetization etc.