Exclamation [Q] Returned Note II User--> Bootloader/Rom Questions

Hey guys,

I'm back on the note II with AT&T.

I am currently on the MH3 build with Android 4.1.2 and was wondering if it is smart to take an OTA update for 4.3. I did a few searches regarding the boot loader (I heard its locked now? what?!?)

Additionally, I would like to root my phone and install a custom rom. I see that CleanRom is no longer supported and was wondering if anyone has stepped up to the plate to provide something of a similar caliber? (I want to install ad block and greenify)

The features I am looking for in a rom:

1. Stability <--- need it to be safe for work.
2. Removed AT&T apps/debloated
3. Battery Life
4. Speed

Some recommendations and advice would be greatly appreciate!