I've been pondering getting a GPS. Phone (whether iphone or android) works great for some things, but has limitations :
- requires taking gloves off to do anything. And it is not rare for software to crash, or to have annoying popups or reasons that mean you have to stop to recover the navigation.
- Weather : heavy rain (although modern ones are less affected), overheating in the summer
- GPS lock : had phones work well, others were an absolute nightmare. Latest was pretty good up until recently, now getting GPS issues. Previous phone got binned after too much hassle regarding GPS lock.
On the plus side, phone is great for trafic, speeding cameras etc.
I think I'm going to go with both, at least for now, and bold the phone on the side of the GPS. Both phone and GPS could be complementary on long trips.