I have been using the framework successfully for quite a while in my applications and it performs well. I have put a full page together to explain how to implement the framework in your applications along with some example Visual Studio 2013 solutions.
MVVMBlocks is available as a NuGet package and can be installed from there from within Visual Studio. The NuGet page for MVVMBlocks can be found here. I’m planning on releasing the source code to the framework, so you can see how each of the MVVM framework elements have been implemented. This will also enable you to make any changes you see fit to the framework. As soon as I have released the code, I will post an entry with details to where you can download/view the code.
I would be really pleased to hear from you if you decide to use the framework. If you make any code changes, I would be more than happy to hear about these and potentially implement your changes in future versions of the framework.