As an ex broker I agree many are a bunch of muppets! They are a bit like economists, in that they will always know tomorrow why the trade they recommended yesterday didnt make money today!
One advantage however with full service is that most only take the ACH margin. Being risk adverse, I hate when brokers like commsec take enormous margins, which forces you into a margin call position when the market moves the tiniest bit against you. Full service means you can negotite when you finally do get into margin during huge moves against you. I dont like the idea of a computer taking over and liquidating my option positions by absolutley smashing them into the market right on the open.
having said that, my broker charges $110 a side, which is insane. For trading massive volumes only.
Oh and one final thing, a full service broker can also call market makers for you and get flow in some of the smaller names. But like i said, you have to be trading huge or not worth it.