pro's and cons of MEF vs Portable Areas via MvcContrib for collaborative programming

I've been looking into MEF and Portable areas and the pro's and cons of using these in a collaborative programming environment.

I've found the following article

http://www.thegecko.org/index.php/2010/06/pluggable-mvc-2-0-using-mef-and-strongly-typed-views/

which states

MEF was chosen over other solutions such as Portable Areas as it allows all plu开发者_运维百科gins to be composed together as a single site at runtime without the assemblies needing to reference each other.

I haven't found any real in depth comparisons between the two technologies, although I did find the following question which didn't have any answers.

http://mef.codeplex.com/Thread/View.aspx?ThreadId=210370

Have spent a while searching, does anyone have any experience with these two technologies and/or insight into situations where one would be preferable over the other?

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I've never used Portable Areas, but I do think it is worth mentioning that one big benefit of MEF over other solutions in my mind is simply that MEF is now included in Framework 4.0. If it is true that Portable Areas requires assemblies to reference each other, that would seem to be a big negative compared to MEF (that is if a pluggable architecture is important to you).