I received my nav update today and installed it. One word of caution: keep the packing slip that comes in the envelope, as it has the 16-digit key you need to authenticate the update. I had misplaced this amid a bunch of Christmas clutter in the house and was worried I might have thrown it away. I called the toll-free number, gave them my order number and they gave me the code over the phone. Unfortunately, they told me a couple of characters that were supposed to be "I"s" were "1"s and the first authentication attempt failed. It was cleared up after I called them back.
The update process itself is very simple, taking a little over 10 minutes after you swap the old nav SD card for the new one a couple of times. That's a massive improvement over my 2011 LE, which required the car to be running while 5-6 DVDs were swapped out over the course of about 90 minutes.
While I haven't had much of a chance to really check it out, an early search of the map was disappointing. A major highway near here which has been open for yearly a full year still doesn't show up at all -- it stops at a section that was completed over three years ago, just like the old map. I was really hoping it would be somewhat of an improvement. Since other nav companies that do frequent updates have had this road in their systems almost from the start, I'm curious as to what process is used by whoever decides the Nissan updates are "good enough" to go, and when...