If you need to know which is the best Azure datacenter to use based in the network latency with your location, Azure has a solution that can make your life more easy. Azure Speed Test website runs a network latency test from your location to all Azure datacenters. It shows you a sort list with the average latency, the nearest datacenter to you and if a CDN Node is near to you.
The Blob Storage Latency graph is simply fascinating:
Code can be download from GitHub.
Angel Perez Palacios 