Its goals are:
Provide a robust, and quick desktop panel
Make it easy to customise and extend, rather than hide options
Use modern technologies rather than be backwards-compatible
Make it easy to hack on!
Why do you need SlickPanel
From application creator
When I switched to Oneiric, I tried Unity and GNOME Shell however I found I preferred my classic setup of GNOME Panel and used a external application launcher.
However, I was surprised to find that GNOME Panel had not very well maintained in Oneiric. In fact it is buggy and I had to go through some effort to get Indicators working on it.
After looking at GNOME Panel and other options (such as wingpanel) I realised there was not a quick, stable, extensible (and pretty!) desktop panel for GTK.
So I made one
Install SlickPanel in ubuntu 11.10
Open the terminal and run the following commands
sudo add-apt-repository ppa:and471/slickpanel-daily
sudo apt-get update
sudo apt-get install slickpanel