And TBH this is more of a general Linux thing (assuming you are running Linux on your Pi, you didn't say...) and this is the TurnKey Linux forums (which as yet doesn't run on the RasPi).

Anyway as I said I'm not that familiar with Samba config as all my experience with it has been with the TurnKey Fileserver appliance which has it already preconfigured (good starting point). I could give you some perhaps useful general hints but if you've already been researching and reading, then my guess is you've already heard them, or that it won't be enough...

I haven't played much with NFS either so I'm not really that helpful at all sorry... At home I have all Linux computers and use SSHFS to share files.

The only thing that I can think of that may be of some value is that SMB/CIFS under Samba works similar to Windows file sharing. Except with Linux/Samba you have 2 separate sets of users; Linux users and Samba users. For it to work these need to be synced (at least the users that you want to use for Samba anyway). To compare to Win: Samba users set share level permissions and Linux users set file lever permissions.

Also if you are just trying to access (and mount) a remote share (rather than providing a local share) then you don't need the full Samba; you only need the client stuff (not the server stuff). Although sorry I forget the name of the packages...