I use a basic Bryton 320 GPS. I'm sure it has more capability than I use it for, which is just time, speed, and distance. Simple B&W display that is illuminated at night. Battery life is great. I get at least 10 hrs on one charge, and that is with the backlight on. Also seems pretty accurate. I ride the same route all the time, and the distance measured by the Bryton is more consistent than my Apple Watch.
Mark