i have been using this ROM for the past couple of days, here are some of the problems:
[*]2-4 second lag when using any unlock animation including lock methods (pattern, pin, face...)
[*]3-4 second lag when pulling up keyboard in any app
[*]occasional crash when pulling up keyboard, screen goes to default wallpaper and is unresponsive until force shutdown (take out battery)
[*]some apps seem seem to have a lower resolution than using stock ROM e.g Clash of Clans
[*]occasional glitch where phone randomly locks, or becomes unresponsive
[*]battery life screen on time 2-3 hours with light-medium use. 1-2 hours with heavy use (not a big issue, just like to mention it)
However, this ROM is the closest ROM to making your s4 active into a s6 or s7, other apps such as the music, theme store, messaging, phone, camera etc work perfectly fine with no stutter or lag. this also helps in making your phone look like its on marshmallow, and you can theme it further with nova launcher or google launcher to make it look like stock android. Charging times are as standard, it took me around 2 - 2:30hrs to charge from 0%-100%, battery life is a little lacking, but it is expected as it is a custom ROM.
if you are looking for a stable ROM, i recommend looking at firmwares from Sammobile, as this ROM is isn't stable, however, it will get you by as a daily driver as i am doing now, but you will need to get used to the problems that i listed, until the developers fix it.