I currently own a galaxy s4 with root, it's pretty fast and gets the job done and the root customistation is brill.Some cool apps I would recommend are; ●terraria ●DraStic ●Supersu ●Clean master ●tiny dice dungeon and shattered pixel dungeon
I have my HTC M7 rooted and RUL with a custom Kernel and ROM. I must have for rooted phones is Greenify battery last ages. If you like a clean UI Themer is lovely. Or if you are into DIY Zooper widget/widget locker/Nova pair nicely together of course there is Lighting launcher as well but its not as user friendly as Nova launcher. Wakelock Detector is nice to see what your phone is doing while your not using it. Other things: Waze maps Aldiko Poweramp My boy! nds4droid John GBC lite Cover Xposed Installer Wish I had money for a new phone, really want to look into a Nexus 6 or Sony Z3. I'll probably just wait till another good audio phone comes out tho.
My sister uses the same phone.XD its indistructable many times has she smashed it against the concrete floor and it still hasn't broken.
What custom kernel and rom? I also use greenify but sometimes it gets on my nerves when I want apps to run in the background
The Kernel is one I messed with is based off AGK ASOP and another one. The rom is just a slight edit to Android Revolution HD 82.0