Yeah, I don't think much of any of the battery saver apps. Most play a zero sum game and others cripple the functionality of the phone (and a lot play on the placebo effect). Prior the 6.0, the only tools that really had a good approach were Greenify and Amplify... but both could be fussy and to get them to work properly, you need root and Xposed installed.
I usually stick to three simple guidelines:
1) Get rid of apps that use WAY more resources than they need. The poster child of this is Facebook. The app is complete and utter trash. It fires constant wakelocks, uses 10 times the processing power that it needs... it's the most poorly written, and one of the most widely installed, apps there is. I've long ago removed it, instead using one of the apps that loads the mobile web version in a browser shell.... and make sure to deny it if it asks you to let Chrome notify you... if facebook notifications are that important, have them set to email you instead.
2) Turn your screen brightness to the lowest level that works for you.
3) Get a good battery monitoring application so you can keep an eye on things from time to time. GSAM, Better Battery Stats are two I use.
Other than that, leave it be. A lot of tweaks, like turning off WiFi when it isn't connected, do next to nothing. Some, like going through and clearing the apps in Recents/Overview, do more harm than good (that's why Google doesn't have a 'clear all' button).
If you want to do more than that, things get a little bit more complicated.... To really get the most out of things, you'll have to have root access and a custom kernel. There, you can do things like adjust Doze's settings, tweak the governor settings to optimize things based on your usage...etc.
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