I have a Kenwood in mine. I mainly wanted the backup camera. Three years later they have advanced even more. Now you can get a side or front camera as well.
I do not have navigation. I use a Garmin and try to update it regularly. We move it from vehicle to vehicle. I see some navigation screens that are really nice, but I don't want to spend the $ for multiple units.
I may update just to get the updates on the cameras and phone inputs.