I've tried all the main stream kernels. ElementalX. Franco, Kylo & God's, Some kernels have good battery life at the cost of stuttering performance and others are mostly vice versa. All i expect from a custom kernel is fluid performance and decent battery life (around 5 hours sot).
Kylo is best suited for me as i'm always on LTE. Though it's slightly overclocked it still manages to deliver great battery life. There were multiple days where i find 70% of battery left after 11 hours of usage. My daily usage consists of around 2 hours of calls, multiple email accounts always on sync, 1.5 hours of browsing and little of whatsapp, telegram & youtube.
Kylo combined with ElementalX kernel app will help you tune further more. Minor changes such as selecting governors for cpu clusters will add extra couple of hours of battery life.
Consistency, Interactions of the developer is awesome. Expect 3-4 kernel updates per week. Slightly overkill in my opinion. :P
All said and done this guy deserves to work with google.