Originally Posted by Steve B.

Some of the advantages of dedicated GPS

1) You’re not risking a $600 smartphone on a $20 mount on the h-bar
My LG cost slightly more than $200 and the $15 butterfly mount is quite secure
2) Unit dependent, the GPS unit screens tend to be easier to read in sunlight and in general.
Correct, phone screens are more difficult but not impossible
3) GPS unit’s are generally waterproof, vs. having to get an $100 Otterbox or pay for a waterproof phone. That’s related to the Android/Apple debate as well.
A $10 plastic envelop sold for taking your smartphone on a river ride worked very well when needed
4) Battery life is generally much better on a GPS vs. a phone. That can be alleviated with the use of a battery pack.
A 12000 mAh backup battery was needed once in last year's Amsterdam to Bruges tour.
5) GPS unit’s don’t rely on cell service and have the maps built in. On a phone and if riding in areas with no cell service, have to use a mapping app that has maps reside on the phone. Doable but just another thing to consider.
RideWithGPS uses downloaded maps based on the most recent Google maps. You design your route on your computer and save the result offline. You pass the file to the smartphone and you have it. I am looking at a map-segment of our Holland trip and my phone is in airplane mode with WiFi off.
Many people just find GPS unit’s easier to setup and use, others have done very clever tricks to use a phone, and have demonstrated that it can work as well as a GPS, you just have to read up on all the tricks and apply them
Pick any Garmin unit and read the reviews. You'll find a number of people who couldn't make it work and even Garmin gave up. That was the clincher last year, as I was looking for a backup to the very basic GPS unit provided by the booking company. In the end I concluded using RideWithGPS and a cheap smartphone