Its the same NAV system as on the 2009 Murano, G37, new Maxima, etc. You could probably read the forums the enthusiasts for those vehicles have set up for reviews and comments about their Nav systems. (myG37.com is very active, and as a new Murano owner, I like
NISSAN MURANO . ORG - A Home to Nissan Murano Enthusiasts )
I have the new Nissan hard drive based navigation system in our new Murano. It was expensive, but I rationalized it for its great integration with the other systems in the car, especially the Voice Response system. A lot of functions are inactive when moving, but the Voice Response system allows you to operate many of those key functions while moving. And there are already hacks out to fool the system into believing it the car is stopped, if you really need that.
It is a great touch screen nav system, and based on an integrated hard drive, rather than the more common DVD systems. (the hard drive is also used for the Music Box system)
Functionally is is very complete, and has worked great for the 6 weeks we've been using it. (3500 miles in that 6 weeks)
I have a TomTom One Version 3 portable system, which I love, expecially its price ($140 a year ago). The TomTom only has a 3.5" screen, and no voice guidance but it works well and map updates are a free download. The map updates for the Nissan Nav system apparently will cost close to $200 if you want them. Ouch...
Still, I'm very glad I sprung for the Nav package on the Murano, as the integration with all the car's systems are great, and it includes the audio system with the hard drive Music Box, Compact Flash card slot, etc.
--jayhawk
ps - the myg37 guys have done some interesting research into the hard drive music box system trying to see if they can hack it for increasing disk capacity, directly transfering MP3 files to it, etc. See:
Navigation/Musicbox Investigation Part 1 - MyG37)