[pulseaudio-discuss] difference between Gnome Sound Preferences and PulseAudio Volume Control

[Piscium]

I am running Fedora 13, though my question applies to other versions and other Gnome distros.

On the Gnome panel there is by default (that is, after installation) a speaker icon, and if I right click on it I can get to a dialogue box titled Sound Preferences.

There is also PulseAudio Volume Control which is available as a separate package not installed by default.

The settings available in Gnome Sound Preferences and PulseAudio Volume Control are quite similar : selection of input and output devices, volume and so on.

My questions are these: 
What is the difference between these two applications? 
Considering that I already get by default the  Gnome Panel Sound Preferences do I need the PulseAudio Volume Control at all?

I know this is a very basic question but please pardon my ignorance!

Thanks.