I came from the Note 1, to the 2, to the 3, to the 4... someone keeps knocking on my door... ok, let me stop
And each year it's a subtle yet needed upgrade:
for the 4, it included, a crisper and sharper QWHD screen, better than 1080p and just bright as can be
snappier performance than that of the note 3, by leaps, and you've noticed the instance with the better camera.
it's more of a premium build, the s-pen is more responsive and better at recognizing hand writing... I mean it's a great update, and to make matters worse, I just recently got the note edge as well... the 4 is definitely better, but the edge has some getting used to.