It really depends on how you want to trade if you are looking to trade intraday and scalp 10 points or so per trade then direct market is better. If you intend to take a position over a few days and look for larger moves then the spread is less likely to be a problem.
I have found the latter technique to be profitable with SBs but I can not stress the following enough
I appologise if you have heard the following.
Its important to have a trading strategy and stick to it, nobody says you have to trade every day, learn how the market you intend to trade moves, learn support and resistance levels.