CX9's navigation system is a basic version of what is on Lexus (both from Denso), which is not the best in auto industry. Acura has arguably the best OE system.
There are several advantages of an OE system that a portable one can't beat:
- extrapolate current position when GPS signal is lost
By take speed and steering angle from your vehicle's computer, OE system can do this.
Your portable system will stay where the signal was lost.
- cut down stereo sound volume when the system speaks.
- quick boot up in 2 seconds or less
Those are three of the major advantages of an OE system.
Other than those, I am sure, many will be happy to list their disadvantages, cost being the #1. Expensive map update comes as #2. Poor usability comes as #3.... and so on.
Let the bashing begin...