I have trading with Zerodha since last 3 yrs and very happy with the result. It saves a lot of my brokerage and during my office hours I can use their Kite Mobile app, Its pretty user friendly. Customer service is very prompt though at times I need to be in the Q to reach them but the wait is worth it in terms of brokerage and the services I get. No other discount brokers in India provides so many facilities like Zerodha does. I have also referred clients and Zerodha is paying me 10% of the brokerage.If you too wish to open an account click on link mentioned below
https://zerodha.com?c=ZMPFWU