You will find the best mix of Microsoft Products/Services related to servers, hosting, databases, and many other services at Microsoft Azure.
Administrative Portal, has all needed features.
Billing portal, great detail about your service billing and consumption. Multiple subscriptions.
Wide options and price levels for virtual machines (This is the feature I use the most).
If you need to setup separate accounts to handle different projects and cost, you just need to add extra subscription to your account, and assign the services properly to each subscription, that way you will charge your customers fairly and easily.
Since you find a lot of options and services in a single roof, you may think the Control Panel is complex, but it doesn't. This product is for technical users and IT professionals with Microsoft technologies expertise.
If you need Visual Studio 2013, there is an option to have it on a monthly per user fee that is less expensive than getting the full package, and is integrated with AZURE.
You will find some free tier services, like small MySQL server databases (20 MB). This is useful for small projects and testing.
A good level of documentation is available. with code examples for every mayor development tool.
I tried other service providers to compare, always end with Azure based on Price/Features/Scalability and centralized administration for different solutions/projects, but go ahead and do your due diligence, since not all projects are alike, and you may find another provider that suits your needs. If you have Microsoft products expertise, probably you will be better off with Azure.