I realized I do have one caveat on a phone-based GPS: sharing. I have a regular GPS that my wife and I share, as needed. But If I pay $100+ for a GPS on my phone, then it's mine and mine along. No more sharing. So I'd have to buy two, so she can have one as needed. And that's wasteful, since we don't need GPS's normally. So for me, the GPS app may need to be twice as good or half the price of the comparable hardware to make it worth buying.