I hope you never do. Rock is insidious and puts its claws in everything. Wait til your phone crashes and then you try to uninstall it. And then you try to nuke it through SSH. And then you restore your phone to factory settings, reinstall all your apps, lose your backups (as they carry over the awfulness that is Rock) and rejailbreak.
Do some people never have problems? Sure, but for other Rock as been a horrible experience, me included.
Been jailbreaking since the 3G and I can tell you I would always advice to stay away.
Good luck though! (not meant as sarcastic)