My dad just went from a 3 to a 5. He's the only one I know though. My brother got a 5 too, but he's never owned one.
I've owned a Galaxy S2, Skyrocket, Note 1, S3, Note 2, S4, Note 3 - and now I'm looking for a way out. With every single one I've installed Cyanogenmod or an AOSP like rom. I think I'm done with the headaches of nightly builds, glitchy touchwiz performance, and design language that is inspired by Crayola.
Honestly, the OLED screen was one of the primary determinants of me sticking around. The solid battery life and exceptional camera also were there to boot. However, the Samsung package, no matter how impressive the hardware- has an UNEXPLICABLE amount of jank and clumsiness.
You might have metal on the Note 4, but S-Voice is still a hindrance. You might have incredible battery life, but what's it matter when the phone fights you tooth and nail to push Samsung "innovations". Swiping up - gives you Flipboard or My Magazine or whatever the shit they are calling it. It's just not worth it, and the "experience" can only be endured for so long. At least for me.
If Samsung wants to win over Android fans in masse, there is an easy solution:
1. Offer a Google Play Edition of any existing flagship phone (Note / S) at a fee.
2. Trim the fat on Touchwiz. Call it Advanced Mode, Pure Mode, Performance Mode- whatever you want to cal it.
3. Hire a designer that doesn't watch Nick Jr.