First you will need to use ODIN to go back to the original stock firmware.
Stock Odin for P907A can found here: http://forum.xda-developers.com/gala...t2850564/page1
Stock ODIN for the P900 can be found here: http://forum.xda-developers.com/show....php?t=2724895
For those who don't know how to use ODIN, here is a nce guide for you: http://androidcentral.us/2014/02/how...msung-devices/
Now the next thing you need to do is root using TowelRoot, but DO NOT install SuperSU yet! After rooting use the debloat script in this thread (You run it from your device using terminal, I used the terminal function in ROM Toolbox): http://forum.xda-developers.com/show....php?t=2797540
I only used the option to disable KNOX and the updater along with the option to disable the startup sound.
Once you have successfully done those things, you may now install SuperSU. It will no longer ask you about KNOX, because it is properly disabled and will not cause you any reboots. My Note Pro has been rock solid stable and lightning fast after doing this.
NOTE: You will not be able to update to new firmwares after this.
Please make sure you hit thanks in these guys' threads for their hard work!
EDIT: If Jellybean comes out for our tablet I would not update unless the trade off was worth it to you. Or obviously if an exploit for the jellybean update were found then you would want to. If you did want to update, you could re-enable the updater by using the enbloat script that was with the debloat script.