Ability to output to TV, snes/gba/ps1 emulators, lock screen information, visual tweaking to your hearts content, 5 icon dock, infinite size of folders, responding to texts without closing any app you are using, adjusting brightness and turning wifi/3g/location services/airplane mode etc from swipe down notification center/pretty much any tweak you can think off
my friend if u dont know the benefits then better stay away til u read and see wat jb is, ill tel you why im jbken..
i can get themes , easy acces to toggles wifi 3g data location etc, i can facetime on 3g tether my unlimited data plan look into my phones inside files and folders , move files songs to other files and so much more that i need a lot of time ..
have a look here http://www.youtube.com/watch?v=jLbjMlswX-8
its last years tweaks and also old and in italian so i dont understand as wel but u can get an idea..