I am extraordinarily happy with this $400 phone. If you're on the fence, buy one. Period.
The camera could stand to be improved, but numerous reports point to the problems being software, not hardware, and even as-is, it's head and shoulders over the N4. Speaker volume is fine - as loud if not louder than the N4, better fidelity. Far better headphone fidelity.
Hand feel is amazing. Amazing! The white back surely feels the same as the black back (smooth but not smooth), and the sides and front are identical between the two.
Kit Kat is great. Jelly Bean but with some nice perks.
Speed of the phone is stunning.
You will not find a better phone for $350-$400. You won't necessarily find a better phone, period.
Edit: And the display... oh my God the display. Get one.