For those of you looking for a versatile AOSP ROM (What is AOSP?) with multi-window and floating window like TouchWiz ROMs, definitely check out the latest SOKP ROM.
I have been a great fan of SOKP ROM ever since its birth a few years back and the latest Android 5.1.1 version for the Note 4 is better than ever. Based on latest Android 5.1.1, you will be able to enjoy pure Google Android Lollipop 5.1.1 the way it’s designed to, not a botched version it on TouchWiz.
I also recently switched back from TouchWiz Lollipop ROM to AOSP ROM because I feel like you get much faster performance and stability on latest AOSP Android 5.1.1 ROMs. The developers had a few months to work on them and now I am glad to say they are much stable than their TouchWiz counterparts (compared to 5.1.1 on my Galaxy S6).
SOKP ROM also features all of the customization options you would find in many other AOSP ROMs such as custom system animations, customized quick settings, custom status bar, custom navigation bar, etc…etc… For navigation, you will find many of familiar things like PIE Control, App Circle Bar, and Gesture Anywhere.
Overall, the latest SOKP ROM has impressed me very much and performance/battery life is also excellent so definitely give it a go if you are looking for a good Android 5.1.1 custom ROM and do let me know what you think!