"Any thoughts are appreciated"
You can go to the link below, register for free, and download the owner's and NAV manual for free:
http://www.nissan-techinfo.com/nissan/
I have the RF with NAV & DVD. They seem tightly integrated as far as functionality. For example, if you set a destination in the NAV, turn the guide voice on, each time you come to a turn, the radio mutes, and the NAV guide voice announces the upcoming turn.
The radio links with the DVD in a manner that the rear seat occupants can listen to the DVD through wireless headphones, while the front seat occupants can listen to the radio, CD or AUX (mp3 player). From the front dash, you can select whether the rear seat occupants can control the radio.
So I would be careful as to exactly what kind of integrated functionality you are getting with any aftermarket stuff. Also, I would ask to see samples of the installer's work, as there are alot of hacks out there.
The only thing that I found lacking on the OEM DVD entertainment system was a power inverter for games (e.g. an X-Box). The DVD player has connection for the signal inputs from the game, but I had to buy an aftermarket inverter to power the X-Box. I plug the inverter into the 12V socket on the back of the center console, but it would have been nice if the inverter was nicely packaged OEM into the center the console alongside the DVD player.
My main gripe about the RF stereo is that the 6 Disc changer doesn't play mp3 CDs (It will play CDRs). But with the AUX jack, you can plug an MP3 player. The AUX input volume level is lower than the radio/CD volume level, but you can compensate for that by cranking up the volume on the mp3 player. It would have been nice to have an adjustable gain control on the AUX input.