Why would I use the MSBuild and when would I use the Visual Studio builder?
We’re building a C++ project. So far I’ve just used the Visual Studio builder which works fine, but there must be a reason to use the MSBuild builder, otherwise you wouldn’t have both options, and I want to be sure I’m not missing something 
Hi Paul, a number of reasons for providing both options to users:
For MSBuild:
1) No requirement to have Visual Studio installed on the build agents (as MSBuild comes included with Windows SDK’s (after Visual Studio 2013 this has been provided separately from the SDK: http://www.microsoft.com/en-in/download/details.aspx?id=40760), and thus the ability to target multiple dot net platforms without having multiple Visual Studio installations.
2) Additional flexibility provided by the command line arguments (http://msdn.microsoft.com/en-au/library/ms164311.aspx)
3) Integration with tools that produce / consume MSBuild Project files.
4) Users might want to specifically use the 64-bit version of MSBuild.
5) The ability to write custom MSBuild tasks (http://msdn.microsoft.com/en-us/library/t9883dzc.aspx)
For Visual Studio:
1) Easy to get up and running
2) Compatibility with the greatest amount of project types and configurations (eg unmanaged code)