The GPS works pretty well. Takes a few minutes to lock onto the satellites after turning the radio on, but once it locks it tracks well. The radio displays latitude/longitude, speed, direction and altitude. It's neat watching my GPS coordinates update while driving down the highway.
APRS worked well, but I'm discovering that at 5 watts of transmitting power, the APRS holes are pretty big. Receiving APRS beacons from other transmitters was pretty easy. Getting my own APRS beacon out and received was harder. With my radio in the car with me on the way out to Chattanooga, it beaconed pretty well in the Charleston area, and again in Columbia, but after that nothing. On the way back to Charleston, I was able to connect my radio to Connie's mag mount antenna on the trunk of the car. Outside of the big metal cage that is the car, I was able to receive even more APRS beacons from other stations. Getting my own beacons out was also noticeably easier. My radio beaconed a lot more on the way back with the mag mount antenna than it did on the way out. It was still pretty sporadic and the holes were still pretty big, but a definite improvement over trying to transmit through a big metal cage.
Thanks to a stop at Ham Radio Outlet in Atlanta, I now have my own dual band (144/440 MHz) mag mount antenna (an MFJ-1729 mag mount kit) mounted to the trunk of my car. Now I should have a much longer range on the radio when I'm in the car. Help me test it out. I'm usually listening on one of the CARS repeaters. Give me (KK4JRP) a call on the radio!