I have jailbroken my iPod with blackra1n, and immediately restored it, for I was completely unimpressed. It turned extremely slow, and springboard kept on crashing and crashing, and respiring took way too long. I literally had to respire after every installation. It was terrible. The only advantage was that the installation also installed Rock, an alternative to Cydia, which is much faster, only it has terrible packages. It left me with a bunch of files on my hands, taking up too much space. Spirit, on the other hand is simple, clean, and perfect. Installed Cydia, and thats it! No stray files. I restored it again, so that I could make a video of Spirit in progress. Videos coming soon. Here is an image of my ipod pre-jailbreak.