Just been looking online & although you can do e-mail and calendar while in a call. All the sat nav does is close then reopen and remember your destination. So in fact if you took a call you would be temporarily be lost until you end the call. usefull!! hehe 
Hmmm, I have just fired up the satnav on hers whilst I was on the phone, seemed OK to me, other than bloody irratating

. I think I'd prefer it myself if it did block out the Satnav. Being a male, I can on concentrate on one thing - driving, satnav or phone call

. Guess it depends on what software you are running for the satnav?
Personally, satnav wise, I would rather use the one built in the car, seeing as *ALL* portable ones are poor in comparison. Though will concede, I always have it installed on phone for emergencies.
As we said earlier, we all have different priorities, if one of yours is playing old gayStation games, thats fine

. Just don't knock the other options based on incorrect information you have about their capabilities
