Is the s-pen enough to sway me to get a Note 4? (having had a Note 1,2 and 3)

I had the note 1,2 and 3 and didn't use the in built stylus much- usually it was faster to use my finger. I have a note 8 and use a stylus on that a lot- that's due to the larger screen size and the fact that I'll usually sit down and use the Note 8 for a longer period. 

I do use a stylus from time to time for writing on devices like the Note 3, gFlex, Nokia 1520..., using slide keyboards (like Swiftkey). After trying a lot of different styluses I settled on the Bamboo Duo stylus - which feels great to use and to hold; doesn't impact battery life; can write on paper  and has a jacket clip which I find useful. I preferred writing on my Note 3 with the Bamboo stylus compared to using the Samsung stylus. The other stylus that I enjoyed using for notes etc was the Evernote Jotscript (though I prefer the Bamboo Duo). The Jotscript works very well on the iPad and on the LG Flex (the curved screen making it a pleasure to hold and write on, with any stylus).

It comes down to what's important to you & how you use the device. However, the Note 4 stylus isn't enough of a benefit to make that the deciding factor for my usages. Especially when I have other styluses that I prefer to use on a device the size of the Note 4.

(Bamboo Duo stylus on Amazon)