i personally love salvage mod for aosp and Eternal Prophecy for Sense
eternal prophecy updates quickly and often so very few bugs and is optimized whenever something new is released. the kernel does play a huge part but for the most part i only worry about the kernel for aosp, as EP comes with 4.3.4 from netarchy. after that its changing your sync settings, display, if you decide to use setcpu(i do).
also my original evo battery has 1.5x the life of my replacement evo battery(i have both, my first evo broke and they only wanted the phone and let me keep everything else), hell if i can understand why