If the N4 is a minter then the N4 is the much better phone, better hardware and possibly better software support, 4.4 is rolling out for it now, whether it gets the next version of Android is debatable, the hardware is certainly up for it, it is down to Google or not, at 18 months they may well say support ends, 3rd party devs will almost certainly be giving it some for a number of years should you want to go down that route.
The N4 is also supposed to have an improved battery chemistry that's good for 800 charges so that's not going to be an issue with it for a good while either.