Before we sign up for any hosting company to host our app or pages, i think it probably is good to find out the speed so that if it is too slow, we may as well pay a little more to find a better place to put our app. the question is, is there a way to find out some sites that a hosting company is hosting and what is the best way to test the speed of the site? (is using "ab" command one of the best methods?)
Check out this blog http://www.joelonsoftware.com/backIssues-2009-02.html from Joel on Software about http://www.akamai.com/
It details your packet are routed to a Akamai node and then from there go to the fast lane to the nearest Akamai exit before the end point.
I don't think that you can generally find out the speed of a site as that is a function of the route to your site and how that route is set up. If a provider has a route to Toledo before routing to the next town the speed may appear slow even if they are running the fastest type of link.