Just sips on battery and even RAM. My favorite live wallpaper on Android was the Nexus Revamped..
On my SE, I have 3D parallax of a lion, Spider-Man, Iron Man, and whatever. Don't use it. Changed my settings back to static and not dynamic. Just put a plain black wallpaper to save battery.
The novelty wears off with live wallpapers like a koi pond, 3D parallax, or even video wallpapers from way back in the day thanks to jailbreak.