I have been trading for quite some time now and know very well the different platforms available as I have traded on the Share Khan, ICICI Direct, Reliance, India Bulls and Kotak by far is the worst as far as service is concerned. As for the platform versus cost, it is very good, but service, I dont want to make mention at all.
ICICIdirect may be expensive, but I have never faced a problem with them so much so I have never had the need to call customercare.
India Bulls have a good site, I have fed them some suggestions and if they incorporate then they will be the best trading platform available and also the most expensive. No doubt to justify that they give you 12 time exposure for intraday, for which you have to shell out the moolah, whether you win or loose, they get their due.
Their signature line of Kotak Securities should be "We are Kotak Securities are here to help you, ONLY if you dont have a problem, BUT if you should have a problem, go sort it out yourself"
If there is a problem, they blame either you or your PC. I have finally decided to quit and close my account.