The N4 is my top current choice if my iPhone 4 dies. I switched from AT&T to Straight Talk, jumped through some hoops to get data working but works fine now, and the unsubsidized N4 price is a bonus (half of the iPhone 5 price!) I've read nothing but good reviews.
Shame there is no retail presence. If I play with a demo model long enough I might be tempted to switch sooner.