Are the free Win 7/8/10 VM's Microsoft provides for testing purposes restricted or any different than their counterparts?

To learn more about those VM too on my side, I asked your question on a private channel I have with MS and from a well known IE MVP I got this answer;

There are no limits and they are not stripped down.

nb. Limit for using the VM for testing anything, not for the actual activation limit.

Functionally there are no restrictions on the system / OS. They do, however, maintain the usual evaluation licensing restrictions -- meaning they are for short-term, test use only. If you're going to do anything long-term or production based, you'll need to get the appropriate licensing.