I have not used EmguCV, but I have used OpenCV for a while now.
From SharperCV's website:
The Emgu CV.Net wrapper is our current recommendation if you want to use OpenCV.
And, OpenCVDotNet looks more like an academic sandbox, so if it were me, I would use EmguCV for any of my research projects that involved C#. Mainly because it is being actively maintained, and it has the most features of the available wrappers today.
