If you have updated your Galaxy S5 to the latest NHA ota update you can root it by flashing the NCG kernel, rooting, and then reflashing the NHA kernel. Once this has been achieved you can then reflash the SafeStrap recovery. Once you have flashed the SafeStrap recovery you can resume installing rom. There is already a stock rooted NHA rom. This rom can also be used by other developers as a base so expect plenty of other development to roll out quickly.
The rom features are limited since this is pretty much stock with root. Features include free native wifi tethering, zipaligned, busybox, initd support, odex and deodex, KNOX removed, removed verizon updater, removed verizon videos which frees up much needed space, fix extSD card write, extra toggles added, enabled infinite scrolling, and more.
Via XDA