I actually belong to a consortium member who is not currently using Contact Permissions.
I've converted several organizations from using other various approaches (attributes,email/mail/phone indicators, etc.) to using Contact Permissions. It's a bit confusing to some end users up front, but ultimately permissions work much better and provide more consistent results from what I've seen.
I'm waiting for v16 and will add the Plug In. I have it mapped out and I envision it as a great improvement.
We're beta testing v16 so rather than having to map it out multiple times I went ahead and put it in our live system. I agree that it can be confusing at first for end users but am overall happy with the change.
We're putting off v16 for now (and probably for a while) for a number of reasons, but one is that we expect it to be a particularly big lift for our organization. That's why I'm trying to knock out communications preferences now.