I find it odd that the website for a .net web framework is mediawiki, written in PHP. If a framework isn't used for its own site, doesn't it make said framework suspect in the first place? It lends less credibility than if it just used something like Google Code, GitHub, Sourceforce, etc.
Using off the shelf components just says they won't reinvent the wheel. If I remember correctly, Bistro uses a django-esque templating model. Not reinventing the wheel or creating another "instant blog" tutorial is fine by me.