That "shares showing up in Network Neighborhood" thinks is in fact rather complex.
It used to be a simple NetBIOS feature in that file servers would broadcast their available shares to anyone who cared to listen.
But NetBIOS is old en deprecated (even by Microsoft) so recent Windows versions (both servers and clients) don't default to it anymore.
(shares are supposed to be published in Active DIrectory so clients can look them up, and access them directly over TCP/IP, without the NetBIOS layer in between)
It's possible that recent samba versions, aiming to mimic Windows file sharing, don't broadcast all that stuff by default.

On top of that, there are a number of settings in samba that can make shares invisible to users that don't have access rights (access based enumeration, hide unwriteable, ... )


try adding this to a share definition and see if it makes a difference
Code:
browsable = yes
you can check defaults values (not present in smb.conf) by running
Code:
testparm -v