Typically algo/ quant traders wirte their own software, as most of the retail programs availabe lack flexibility, or only work with one provider. To have a computer trade your money automatically, you want to know you can trust it. Lots of free programs will automate a moving average crossover strategy, but they wont tell you when to trade it, or which stock to trade it with, or what leverage to use. thats without spenging tens of thousands on black boxes and upgrade packages.
