This poll is a no-contest! Imagine not having Zerodha in the list. Agreed that they are new to the business, but they have brought about a change. And that is the key. Broking in India has never been so customer-centric. I have accounts in over 8 brokerages and I know what is good and what is not.
I have been trading on Zerodha's system for over a month now and 'touch wood' I haven't yet had a single problem in terms of connectivity or margins or customer service. The costs are really low, too. For the first time, I don't have to sit and calculate how much brokerage I have paid.
Zerodha needs to be added to this thread if this has to be a fair evaluation of which is the best broking firm.