I have just upgraded my Note to 4.12 TouchWizz ROM.

Firstly, somethings look faster (but actually aren't).
Google Now is a great feature which doesn't cater to me.
Camera improved but it, and Gallery App are prone to FC.
I liked the UI I had on AOKP (status bar, notifications, lockscreen, recents, 360' rotation, hold back to kill).

But the TW UI is "close enough" but falls short.

I will ultimately stick with TW ROM because Camera is good (AOSP is terrible) and I have the Modded Split Screen feature.