steve you traded options with SB's you must realise the spreads are massive!
However typical spreads on the underlying are quite big too. The only gainers are the market makers because option spreads can be as much as 10%-20% market makers are guarenteed to get a better fill then you think, whether long or short. However in less vol markets short selling options tends to be typically well offered therefore shorting option in size can be more difficult. As a private options writer you can have your eyes ripped out. But sometime its worth the trouble to trade multiple option strategies.
Be aware IG option expire basis cash and not EDSP like the underlying///