I used to asnwer alot of these questions before but then found that marketing partners will write in lengths good thing about their company.
All discount broker charge more or less same brokerage and also their brokerage doesnt matter much its very negligible when it comes to stock market.
I have traded with zerodha and Tradesmart online. What i suggest is have multiple demat accounts in every family member’s name.
It is handy in terms of IPO applications and even trading at times.
All the best brokers, Even NSE the exchange itself suffers technical glitches at times.
I can say that charting pattern and other services of Zerodha is good but the customer service of Tradesmart is best.
Moreover, Please google the bad reviews about each broker as no one will tell you about ill effects of each broker.
I will suggest you to open a demat account with each broker as it will cost you approximate Rs. 400 an year which is Rs. 1 per day.
Welcome to market. Happy trading.