my 4S is totally pure!! i've never felt a reason to jb, i enjoy the function of the iOS just as it is
Absinthe made my iPhone better.
Jailbroken. It doesn't respring often enough for it to be annoying. Jailbroke in order to get the os7revive theme then installed a bunch of tweaks to make tasks faster & more accessible. My upgrade this year will only be ios 6, & a new theme called paragon that'll give me the windows phone 8 start screen. Best of both companies.
after some days that you jb your iphone it will be slower because of cracked file system and had less available ram space
if you see your ram via Some apps like "Pkiller" or "Memory doctor" you can see that Many Capacity of ram is wire(=using by file system(kernel) )
i think that unjail breaked iDevice have better performance and have less lag or Hanging( =Force close or stop working )
My iPhone 4s-64GB is on iOS 5.1.1 that when i jb it and I install about 16Gb app and working with theme and switch quickly between apps its crashed and sometime its Hanged !
But when I restored and it become pure i install 57Gb app that never Hanged or laged or crashed !!! but sometimes it alert me that you dont have enough space and automaticly delet some application document or save data !
I use many apps at same time and sometimes i forget to quit apps ( via double tap on home and close them ) because of i cant see any lag and dont decrise speed !
you can see via using some app that are in utility categories and show system state...
Thank you