bweN diorD is correct with an Unlocked Bootloader you are in good shape to take the update, even if Root is lost it can be recovered. However, if you have JUST Root, there is a risk of losing Root with the Update. I lost Root with the update as I was testing something out, which the Update failed (I also used a manual copy of the update that I uploaded through the Stock system Recovery.) Anyhow, what seems to occur is almost immediately after the update and the system reloads, there will be a request to update the binaries, which this will cause ClockWorkMods SU Root to fail (Chainfire's SU is outdated, use Motochopper to change to current ClockWorkMod Version.) For those with just Root, what I would recommend is installing Safestrap
(if you do not have Safestrap installed already click here and install version 3.12). With Safestrap installed do a Backup of JB 4.1.2 version 9.16.6 or 9.16.9 first. I recommend this as it will keep a Backup of the current JB version with Root, if for some reason Root is lost even with using either OTA Rootkeeper or SuperSU, you should still be able to Flashback or Downgrade from the Safestrap Backup, I still recommend waiting for a proven safe version or you can simply try to restore Root and try again. To restore if Root is lost, go into Safestrap and install the backup, this most be done through reboot, the Safestrap robot icon appears between the Boot logo and the Boot Animation.