Zerodha and RKSV both are good. Interactive Brokers have some additional facilities , they being present in many countries, their front end and backend platforms are world class......but with that comes strict discipline....if the margin in the account falls short, they will just liquidate the outstanding position without checking with the trader, as the whole RMS is fully computerised......
If a trader can trade well, he can make money trading with any of the above brokers.
If a trader cannot trade, give him best tools and he will mess it up...
Smart_trade