Couple of good readings regarding MEF usage.
- MEF introduction article – http://www.informit.com/articles/article.aspx?p=1635818
- http://brendanforster.com/mef-import-vs-importingconstructor – article describes difference between [Import] and [ImportingConstructor] attribute usage. Also describing design difference between using property setters and constructor initialization.
- Recomposition and constructors -http://codebetter.com/glennblock/2009/03/21/recomposition-and-constructors/