I tried the Google edition 4.3 last night. Heres a link( http://forum.xda-developers.com/showthread.php?p=43216973
) To be honest I didnt like it.. I couldnt find any changes due to the android version. All the changes were from being built onto cyanogen mod, aosp. Which I don't like because its buggy. Has very low volume bugs. Has none of the s4s signature features. Bad battery life.. if I was to choose a aosp rom it would be pacman because of its enormous amount of features and settings. But it has the same cm bugs.
I did however find a really great rom thats built on tw 4.2 but has lots of cool new features and settings. Its called graviton.
Really good rom. Touch wiz based with no bugs.. Here's a link. http://forum.xda-developers.com/showthread.php?p=43809526