yep! or sort of.
I am not sure about samba public shares as I never needed one. I just love linux's groups handling; it does a great job through your smb.conf in creating the right open share for the right group of people so you will never need a wild open public share.
Coming back to your question, while on a windoz server your PAM is obviously consistant across authentication and sharing, when using samba you are asking linux to emulate windoz's CIFS networking.
Linux/Unix native way of networking is NFS and when using NFS you do not need to create users again when you need to allow them on the network.
There are however a few options in samba which automatically create samba users when a new linux user is created or, I repeat, if you join a windoz domain with samba, when a new user in windoz is added.
That should make your maintenance much easier.
QatQat
If I could have sex each time I reboot my server, I would definitely prefer Windoz over Linux!