S5: Best ROM&Kernel for battery life & stability

I'm looking for the best S5 900F (klte) rom&kernel with a focus on battery life and stability. Customizability, user friendliness and 'snappiness' are also important. Heavy performance less so.
I'm currently on CM 12.1 nightlies. Not unhappy, but battery life isn't spectacular and stability is so-so. And I was hoping there were perhaps even better things now.

[Q&A] [ROM][KERNEL] Xperia E OldButNotObsolete

Firstly, Thank you very much, The Brain Candy, for your good work on XperiaE's ROM+Kernel. The best for me is the system fonts, super sharp and readable.

Secondly, is it possible to have actual Network Operator Name behind SIM Card Name on notification bar ? e.g. SIM1 (Vodafone 3G) .... SIM2 (T-Mobile 2G)