preferred shutdown method

[Kaushal Shriyan]

Hi,

Which is the preferred method of shutdown of a Linux Server and any
specific reason to go with the specific method.
Please suggest/guide

Shutdown:

    * init 0
    * shutdown -h now
          o -a: Use file /etc/shutdown.allow
          o -c: Cancel scheduled shutdown.
    * halt -p
          o -p: Turn power off after shutdown.
    * poweroff

Thanks

Kaushal