Carbon 4.3 is a bit less popular rom but termed to be good in performance. This rom is for those who do not needs additional features. But needs a complete stable device that can perform well and give proper output. It is good for increasing productivity of your device and works really well. The interface is very light here. It has a simple lock screen and customization options. The UI looks really thin.
This rom is loved by those who want a fast performance mobile phone. It has capability to boost your device performance in terms of multi-tasking. It works really well and has no performance issue. I had tested this rom and quiet happy to use the same. The only thing I said that it does not provide you a good amount of customization stuff. It remains low on the output and works fine. So if you think your device is going slow on the existing OS just replace the same and add this one.