I have done several trips using only my phone. Im and Android guy so this perspective is for android (I hear enroute for Iphone is very good also). I use co-pilot, I have been in a love hate relationship with it since the beginning. It works but is not perfect. I find that is the case with everything though. I build all my routes in Motogoloco.com it uses google maps with their interface, you can save and export routes for any GPS known to man so you don't have to worry about the format. The site is great and I have no issue with it, make sure you put a few extra waypoints because your GPS may not calculate the same. It is difficult mapping in the winter because roads that are closed are blocked on google maps and it sends you a long way around to get to an open road, no fault of any mapping system though. When I export to copilot it works great. I download the offline maps so that part works great and I need no data service for it to work perfect. Finding a gas station along the route, a restaurant or hotel is not good with co-pilot. I usually switch to google maps for that. It would be nice to have something all integrated in one. I still want a GPS that I can tell I need gas in the next 50 miles and it will pull up all the stations ALONG my route with the best price highlighted. I'm sure someone will do that in the future. I use a Samsung S7 that is waterproof but what is misleading is once the charging port is wet it will not charge until it dries. I large ziplock bag fixes this problem but it is one more thing you have to bring with you. The last trip I used the ziplock bag 7 of the 9 days, after all the use the bag gets a little hard to see through. With the screen full bright & a full charge will not last much past an hour or so with bluetooth, data and screen time. I have never had an issue but it has frightened me several times. I also am nervous knowing my only source of communication is my map also, I would like to have separate systems since I don't really need my phone much while travelling. I am seriously considering a dedicated Garmin for mapping and music streaming of MP3. phone will only be a phone and backup of GPS if needed. I have had the charging on the phone quit in extreme heat, again I have never been without but it does get scary in the middle of nowhere and your phone is overheating and wont charge.
My issue with google maps is the limited number of waypoints since I like to route my trip prior to leaving. I just don't want to mess with that many google maps.
Waze is great for riding in populated areas as it will give you the most accurate traffic updates, road hazards and police activity but I find it pretty much useless for planing a long trip.