MSDN hosts a number of excellent blogs including the .NET Framework Blog. They are not exclusively .NET:

In VS2013 RTM we introduced the Performance and Diagnostics hub with a bunch of tools that help you diagnose issues during your Windows Store app development. With VS2013 Update 2 we added two brand new tools: CPU Usage, and Memory Usage. We also made all the tools in the Performance Diagnostics hub applicable to Windows Phone 8.1 development.

We also enhanced the .NET memory dump analysis feature so you can now inspect values of objects from the dump file.

It’s also worth highlighting here the addition of the JSON Debugger Visualizer to Update 2.

You can use the CPU Usage tool in the Performance and Diagnostics hub to see where the CPU is spending time executing C++, C#/VB, and JavaScript code. The tool works on Desktop apps (including console and WPF apps) and Windows Store apps. It can be combined with other tools in the Performance and Diagnostics hub and offers a live CPU graph during collection, fast time range selection, thread filtering, and Just-My-Code. The Memory Usage tool shows (wait for it) memory usage and supports Windows Store and Windows Phone Store apps using C#/VB/C++ and XAML.

Check it out. And check out other developer tools blogs on MSDN.