Sorry for the offtopic.
I had only horror experiences with SAMBA 4,
Usually the scenario is:
In order to save money for licenses the customer "implements" Samba AD only to fuck up the whole infrastructure and then I am summoned to save him overworking myself to death.
And this happened more then once.
So Thanks, I will pass. IMO it is not suitable for organizations which are heavy dependent on other Microsoft products and services.
It maybe more suitable for other non MS infrastructures alongside with other free/opensource solutions.