AFAIK (from messing with getting Linux to authenticate against a university AD system a few years ago) the best-supported way of replicating AD in Linux is Free

AFAIK (from messing with getting Linux to authenticate against a university AD system a few years ago) the best-supported way of replicating AD in Linux is FreeIPA on RHEL, since everybody less corporate is probably going to use a less corporate protocol But Windows Server is IMO Microsoft's killer product. It's very good at what it does, although using it with Linux clients you'll be missing out on large parts of its functionality like GPOs, WSUS, etc