[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] stan.s:
FWIW

I have stock rooted LG1 and I had installed Google Now.

This prevents using the CWM Zip that has been created zine the googleTTL.apk checksums don't match.

I also have Mobile Odin Pro and I attempted to use it to install the OTA directly. Mobile Odin Pro will inject a root and SU into the binary file from ATT/Samsung. If you don't have Google Now and have only frozen your apps with TI (or whatever) you should be fine using it. However if you have Google Now, again, the googlettl.apk will fail checksum. If you overide the checksum and have Home2 installed you will go into a boot loop after the system restarts because the Android system mui can't determine which program (touchwiz home or home2) to use. Even though it presents a menu with both programs, and you can select one or clear the defaults but you can't clear the error and it keeps conning back.

SO, if you are going to use Mobile Odin Pro and have the HOME2 app installed, it seems that disabling it (or uninstalling it) prior to applying the OTA would be best so that the system can completely start. You won't be able to restart Google Now anyway since the apk will revert back to the non-universal search and have to install that also.

The OTA will also remove the CMW installed and you will get the normal Android Recovery menu. It is possible that resetting to factory defaults will clear the boot loop but it will also clear your data and apps. Since you can still use ODIN (PC) to install a firmware, you can get back to a rooted stock easily.

Update:

I re-installed MrRobinson's rooted firmware from here: http://xdaforums.com/showthread.php?t=1739426

This included installing the CMW, since the update that the Mobile Odin Pro made from the ATT OTA had a new bootloader (the android default). As well as restoring the Universal Search as described in the same page 1 post.

Once the reboot from desktop ODIN happened, I still had conflicts between Home2 and TouchWiz Home, but these could be cleared with selecting a default, TouchWiz (Google Now isn't going to work anyway). I uninstalled Home2 and rebooted.

Rebooted, I was getting a android .acore error every 3 or 4 seconds. Just press OK and work through it. I installed the CWM via terminal as described in MrRobinson's post. (( I installed 6.0.1.2 non-touch and used copy/paste and gmail compose to edit the copied lines from MrRobinson's instructions to the right version.))

Once the CMW was reinstalled, I installed the Googlesearch.apk downloaded from the same post again. The error with the acore was still happening.

I then installed the full L9 CMW flashable form here: http://xdaforums.com/showthread.php?t=1896773 This updated the system and modem and some of the apps, but NOT the Googlesearch.apk

Allowing the system to reboot brought everything up without an error. Since the MODEM was flashed, I had to restore the WI-FI APNs from Titanium Backup that required another boot.

Now to install the Google Now I can install the V7 to upgrade from the V6 that I had originally installed.

FWIW: NO APPS WERE LOST IN THIS ENTIRE PROCESS (except the one that I purposely removed HOME2). I never was asked to reapply my Google ID, etc.