Hello,
I had a similar question in this thread:
As for me, the question is still not completely answered. If I understand it correctly, the main difference is that VDC is a group of resources (VNETs, hosts, datastores), and you can allow a group of users to access a VDC in one simple operation.
Some of my questions remains, though: for example, an user which is member of more groups (e.g. bulk and production) AFAIK cannot choose to which VDC will a newly created VM be deployed (e.g. to distinguish between testing and production VMs).
My intend is to give all my users (students and faculty staff) access to at least some ONe resources, so that they can try things, deploy experimental VMs, etc. And then allow some of them (e.g. students enrolled in a particular course) access some more resources (e.g. access to the private VNET of that course, increased quota to accomodate for the resources needed in that particular course, etc.). So far I am not sure what is the best way to do it.
Hope this (at least a bit) helps,
-Yenya