I have the wahoo. Once you’ve set it up – with the phone – you don’t need the phone again. But you can – if you want – customize en route. Get the phone, fiddle a bit, and two secs later your new metric is on wahoo.
It will load via wifi as soon as you’ve pressed stop; get an alert from the auto link to strava generally before I’ve opened the back door.
The wahoo is much more user friendly and has a much more readable screen. The route mapping (only through RideWithGPS admittedly) is excellent, with the LEDs adding a bit of a hint.
No complaints with it at all. Battery life seems very good. Move away from the crappy garmin software.
Course, dunno what it’s like with an Android phone. Apparently not quite as good, but that’s partly as it was helped to fruition by apple.