My own experienced with Carbon 4.4.3 :
Everything is smooth, performance is better than stock 4.1.2 . battery drain fast, but i always have spare battery with desktop charger so for me it's no issue..
Also i OC my GPU lil bit with novathor tweak (built in from roms) . so gaming performance significantly increase too..
For multitasking, i prefer tweaking OOM by myself to suit my needs..
Personally i'm happy with this config...