While NIS has strikes against it, we also need to take into consideration that it works, and it works well. It's a small, clean service that is easily made redundant, and it ties in easily with just about any flavor of Unix you can find. In a greenfield environment, NIS would definitely not be the go-to solution. But in a mostly trusted environment, such as Unix/Linux development shops with many workstations and compute/compile servers, NIS is the answer -- the security risks are minimal, the setup is simple, and the function is solid. Many of these environments have tightly coupled infrastructures that carry the weight of years, and they rely heavily on information distributed via NIS that would be challenging to replicate with any other mechanism. And let's face it -- LDAP configuration is hugely more complex than NIS configuration.
— Why Sun's NIS will never die | Data Center - InfoWorld

So true.