Re: But does it work?
When we moved from SBS to 2012 essentials, we ditched AD entirely. As we weren't using much of the functionality, besides centralised login and didn't want the overhead of dealing with AD.
We are also using Google Apps, which I see as being a potential alternative to AD in some ways (at least in a limited sense). What would be nice, is if some company came up with a way to enable centralised login on Windows machines, but against the Google Apps back end instead of AD.