hey I just read your post and you are asking a difficult question. When I was checking it seemed that speeds were always changing. My office finally settled on an AT financial point to point more than two years ago b/c at the time they were the fastest quotes available to us. But then over time other sources seem to get almost as fast. In fact I stopped using AT and just had a few vendors coming in over our backup t-1 to the internet (even though most in my office still used the AT point to point).
I tell you what, they all seem to bog down at different times. It also seems that soon after a company gets an advantage it gets overworked, then they talk about load balancing and the need for a ring or more lines.
I know I use a few seperate sources of data and executions and I do not know who is the best. Perhaps I should do a test. I do know our office switched clearing firms to get away from one system but I do not want to get into a war of words here. Besides when the system worked it worked great, it was just a little unreliable at critical volume times.
When they are working most are good enough. You know as I think about it the major nasdaq stocks move so fast that the real issue here is who gets you the fastest turnaround on a fill and I imagine that depends on where you are located.