For me, the MD has the advantage that I am in charge of it. And *I* have the means to modify it in any way I like it.
Another major point for me is VDR TV consumption. I have yet to find another networkable TV solution that allows recorded and live TV as good as VDR. That's why I stick with MDs.
If I were to watch streaming content, downloaded content or removable disk based content only, I might change my view. But for now, I love the TV functionality my VDR inside of LinuxMCE gives me.
Both very valid and good points. Being in charge of, and being able to modify, your MD is essentially what i was referring to in my last paragraph. And if you are a VDR user then I can see why loosing that would be a big hit.