As CM11 is Android 4.4.2 KitKat based ROM, you will get the feel all KitKat features. Cyanogenmod is one of the most famous after market firmware known for it stability and some additional tweaks. And thankfully Cyanogenmod 11 custom ROM has already been compiled for it. One of such low end popular device is Samsung Galaxy Gio. So the custom ROM is only way through which you will get this update. But still it is very unlikely that any company will release it for older mobiles. It is tested that it works flawlessly on low end devices. One of the best feature of KitKat is light weight OS unlike previous versions.
Nevertheless performance wise it is better than the Jelly Bean. As we know that Android 4.4 is not a revolutionary update over Android 4.3, there are not many significant changes in UI. Recently Samsung released official Android 4.4.2 KitKat update for their flagship device Note 3 and subsequently thinking to release for Galaxy S4.
