Zerodha offers zero brokerage on equity delivery trades and has the highest number of active clients. It provides a user-friendly interface, back office tools, and an educational platform. Upstox offers minimal brokerage and affordable plans, has the second highest number of active clients backed by Ratan Tata, and provides advanced trading software. 5paisa offers advanced trading tools, flat brokerage plans with premium plans at extra cost, and adequate educational content online, while charging for additional services like portfolio analysis and research tools.