4.3 is tough. I opted not to upgrade. Running a CM 11.0 at the moment which is actually kit Kat. LOVE it. I read that when upgrading you can still revert back to 4.1.2 MC2 stock but the boot loader will remain MK4. That has been giving some issues with rooting but I think there might be a fix already. Google it. I am not sure if I'm allowed to refer to other forums
Sent from Bobby's Intergalactic, Planetary Phone