That is a valid point on the maps Tom. I have the Garmin RV GPS with lifetime maps as well and for the most part, I like it. I also have the wireless Garmin camera, but I've never used it. I was thinking I might go with the in-dash touchscreen radio, partly because I am a tech geek and can't help myself, but also to eliminate the overhead Sony monitor for backup.
I would install the Garmin backup camera in the rear bath window and use it for a continuous live view of traffic behind me on the Garmin - a horizontal view that is not available with the backup camera installed by Phoenix near the roof line. I guess if I'm willing to do that, the sluggish response (if that is indeed the case) on the touchscreen nav would not be an issue since I could just use my Garmin.
I also noticed the Xrite radio has a microphone and it displays a speaker button when viewing the backup camera. My wife went behind the PC and spoke to me, but it turns out, the standard backup camera installed by Phoenix does not have a microphone/speaker. Earl said he could install a camera with those features, so I could hear my wife and vice versa when she is spotting me while I am backing. On second thought, that might not be a good idea!