I personally hate the itunes software as do most of the people I work with..
Is it easy to switch back? yeah.. theres a program you use to install and uninstall the firmware.. you can also dual boot with this software (go back to ipod firmware for a short time)..
I love the skinning feature.. copying music straight to the drive and not having to go through itunes.. priceless... they added some features that weren't part of some of the older systems.. like games.. video support.. more acceptable music types.. etc.. I had an old color/photo ipod I decided to try it on.. I give them a lot of props for making a very cool app for everyone..
They also added some cool features for the blind.. you can add a voice to repeat everything to you, so you don't have to see the screen in order to work the ipod..
Do I recommend it for everyone? no.. but for those who have an ipod collecting dust.. yeah, it may revitalize you're old ipod..