I am happy with E-trade. like a good broker, if the SP happens to be a fraction below your buy-limit, that's where they'll get it for you! very fast & precise & lots of additional services (quotes, news, portfolio etc)
2 weaknesses: not the best with options, also higher brokerage.
the other: there's a time limit. during a day's trading, you'll have to enter your password etc a dozen times. why they can't keep their platform open like e.g. Maquarie CFD, I'll never know. (I don't mind confirming trades by password, but it's annoying when I want some quotes & they tell me I've got to sign in again after maybe a quarter of an hour).