If you like AOSP there is a new Rom for the Verizon Galaxy S4 that is right up your alley. It is based on the Slim Rom but includes an sick theme that will make your device look totally new. The OSE rom includes a Dark UI that can be toggled on and off. Not only will this rom give your device an all new look and feel it also adds performance enhancements through tweaks. There are some other custom mods that add plenty of extra functionality to your device including Multi-Window, PIE Navigation, Custom Navbar options, Custom clock options, custom battery options, CRT animation control, init.d support, init.d tweaks, every feature included in Slimv3, HALO, system app remover, onthefly density changer, app ops, omniswitch, lockscreen notifications, suspend actions, wake lock blockers, and much more. To install this rom you will need to be running the LOKI hacked bootloader, and will need a custom recovery like TWRP installed. You will also need to flash both the rom and the Gapps. Head to the link below for the download.