I used to be a Android fan and advocate since Frodo. But since 4.2 and up, my love for Android is going down on every upgrade. For me an upgrade is when you introduce new features and make old features work better. But Android is going backward. Some features end up broken and some others, plainly disappears. Paid apps that used to work just fine doesn't work anymore.
SD Card access - gone
Cifs mounting - Not supported anymore (this one was very important for me)
Battery not as good as 4.2
Lots of apps not working anymore
KNOX is an unnecessary plague. (This could have easily be an option for business people.)(This is Samsung not Andoid.)
Worst of all, Can't downgrade to earlier version.
I'm really looking forward the new Ubuntu Edge, hope it's as cool as they say.