I have heard it is fantastic software too especially for hedge funds and institutions that have to get big blocks of stock on nasdaq. I also heard that it is used at some of the investment banks too. They have a website so you can do a search and see what it says about the software. I was also told that some how they had access to the depth for the ecns, even the hidden orders that don't show up on the normal ecn books. Don't know if it is true or not. If it is true it makes you wonder how much an advantage hidden orders really are.