Azure includes built-in load balancing abilities. In Amazon EC2, you have to create an ELB, set up auto-scaling groups but it is easier in Azure.
Azure-friendly-coded apps will be delivered internally or in Microsoft's cloud. If you write apps that have confidential information like financial data or health care data, not all of your clients will be willing to put their data in the public cloud. In that case, they can deploy your apps internally on Windows. That's sold as a skillset win because you can go from public to private projects. Don't get me wrong - if you master Amazon EC2 development, then you can deploy your apps internally with Linux virtual servers in your data centre, but it's not as turnkey.
Having said that, it wasn't clear that the load balancing functionality is included in the box with internal deployments. If you have got to do a combination of Azure and ISA Server, that'll be a harder deployment and management sell.
