Yup - I travel a lot and use my GPS on the phone with turn by turn directions... if you get on a call, you can get lost. My wife always seems to call me when I am about to make a critical turn....
The other problem is no email or text messages while on the phone.
I rejoiced when I upgraded from an old 8820 to the 3G Curve with AT&T! This is a sad moment to go back in time. On the other hand, just GETTING a signal with Verizon is more important than simultaneous data and voice for now, I guess.