[nwh]

All major browsers allow you to profile each load time of every single resource. Perfect for trying to compare relative latency at a particular location for a particular CDN. Chrome'a is especially good for this sort of thing, look at "network" in the developer tools.

[noelwelsh]

Sure, I can test my latency, but I'm more interested in what my customers are experiencing. For instance, we have a big customer over in east Asia and I have very little idea what latency they get. When we were using Cloudfront a customer in Australia complained that they were seeing timeouts. It seems there was a bug in Amazon's routing table as Cloudfront has a POP in Sydney but their requests were going somewhere much further away.

[gabemart]

You could try a tool like http://cloudmonitor.ca.com/en/checkit.php

[timothy89]

I agree, I use it all the time for quick tests, but for a bit more accurate results other tools would be better IMHO :)