If you jailbreak you cannot allow unrestricted syncing with iTunes, primarily never allow Apple to patch or update your OS since they usually fix jailbreak techniques. It is also now illegal to unlock your phone and might be illegal to jailbreak it under DCMA. Silly Apple users think they pay all that money and actually own the devices.
"Stand your ground. Don't fire unless fired upon, but if they mean to have a war, let it begin here." -- Capt. John Parker