I have been using PIB for the past 5 years with no problems at all. It is perhaps one of the more robust platforms to trade from. We pay only a one time fee of around 900/- for the software. Brokerage normally is at .3 and .03% for each leg of trade in delivery and intra day respectively. Intra day margins of 8 times is given. Now they have introduced intra day margin for futures as well which is 2 times the money in your account.
As for STT and other charges, it is same at all brokers. Findvikas has made a template for all charges. You can download that and use.
The real money in the stock market is not made from savings on brokerage. So don't waste time scouting for lower and lower brokerages. Beyond a point it makes no sense. You have a good broker, a good platform with charting, now spend time learning about trading.
Good luck.