Full disclosure, this is an unofficial Rom that you will need to download from the XDA. Which also, will make you solely responsible for anything that may happen to your device during this process. If you still feel confident in doing so, we have provided the link, but use it at your own risk.
The Galaxy Note 2 is still officially left behind on Android 4.2.2 Jelly Bean. However, that didn't stop OmniRom developers from bringing it up to date with Android 4.4 Kit Kat. The Rom they have developed supports the following device versions: AT&T Note 2, T-Mobile Note 2, and both the GT-N7100, and the GT-N7105.
Given that this Rom is an OmniRom creation, you can be sure that they have done a great job. If you are unfamiliar with OmniRom, they are a group of elite developers dedicated to the people. Now that you know who has developed this Android 4.4 KitKat Rom, you should also know that it has not yet been perfected, and is the first launch of the Rom build. So there are bound to be some bugs and things that might be missing in comparison to the official Android 4.4 KitKat. OmniRom has assured everyone on the XDA Forums, that they will be adding things over time. Which will bring stability and completeness to the Rom, and to your personal experience.
This OmniRom is an AOSP based ROM, which means it is built using Android Open Source code. This means a pure Vanilla experience, unless apps are added, which is what OmniRom maybe referring to in their description of the ROM. Samsung specific apps or functions are usually attached to their own User Interface or UI, called TouchWiz. So the option for multi-window is probably not coming to this ROM.. So if you can live without some Samsung specific apps and functions, and are craving some of that Android 4.4 KitKat love, than this Rom is for you. However, if that is not you, and Smart Rotation is something you can't live without, than maybe this ROM isn't for you.