I tried Microsoft Azure for a month because I received free credits via their BizSpark program. I can confidently say their uptime is the worst I have ever seen. Nearly daily servers would loose access to disks and switch to read-only mode. Also, they lack any ability to snapshot backup servers, which is a basic requirement of a cloud platform.

I know its early, and they are just starting, but I just don't have confidence in Azure. Stick with AWS, Linode, Softlayer.