iTunes 11 is more streamlined and faster compared to version 10.7. However, the graphical user interface (GUI) has changed quite dramatically -- and not to everyones liking. The sidebar for instance is no longer displayed by default, and you can't see a list of your songs in the familiar tabular view without first enabling the column browser mode.
If you are generally happy with how iTunes 11 performs, then you'll probably want to avoid the extreme measure of downgrading to a lower version (by physically un-installing/re-installing). Changing a few visual aspects of how iTunes 11 looks could be all that is needed in this case.
To help customize the GUI, we've written a visual-tweaking tutorial for iTunes 11 that shows you how to make it look a little more like the older version you're familiar with.
- How to use iTunes Sound Check to Normalize Your Music Library
- How to Force iTunes to Check for an Update
- More iTunes Tutorials