title: prism vs mvvm light for wpf
body: <p>We are starting a WPF with MVVM project and have to decide on PRISM or MVVM Light (I am new to both these frameworks). I have read through a few posts but still have a few questions. Can someone please throw some light on the following aspects w.r.t. both the frameworks?:</p>
  
  <ol>
  <li><p>Performance: Will either one framework perform better than the other for any reason?</p></li>
  <li><p>Communication within the app (viewmodel to viewmodel or between modules etc): I have read that MVVM Light has Messenging Service which appears to be fairly easy as well. But PRISM does not appear to have any equivalent. Is that true? How would PRISM handle interactions?</p></li>
  <li><p>Unit Testing: Have read that PRISM supports Unit Testing better. Can we still write NUNIT or VSTS tests in MVVM Light also?</p></li>
  </ol>