Follow-up. I have been using both my hand-held GPS, and my cell phone GPS for a couple of months now. I am a service tech, and I am driving 2-5 hours per day on average. The phone GPS is quick, can grab the address in a couple of button pushes, give turn by turn directions, and will go off towers and WIFI if it can't get a satalite signal. However, it seeks a satalite at each request. And that causes delays when overcast,or poor weather.Some times it has taken more than an hour to get a GPS signal My Magelin Meridian Gold has lost signal one day that I know of, and could not reaquire for most of the day. Beyond that, it has never failed me. It is clearly the better GPS unit for making sure I get where I need to be, but the phone GPS is lighter, quicker on clear days, and no additional weight, but for reliability, the True GPS is clearly more trustworthy.
The only real difference between a good tracker and a bad tracker is observation. All the same data is present for both. The rest is understanding what you are seeing.