I have tried GolfShot on my Apple Watch (series 3 so its slow), along with a GHOST from Bushnell and a range finder. My Bushnell never stays charged, so unless I charge it on the way to play, its worthless. That being said, I rarely use the watch (lately been going completely with out it) and love the simplicity of Front, Center and Back of greens. I am not accurate enough to nail the pin, and if you know the pin placement you can make your club choice based on if its F, C or B. I also like the rangefinder for what others have said. Its light, batteries last forever, and gets you a real distance (I bought a Precision Pro NX7 non-slope for $120 refurbished, and its amazing for the money). If I was only given one choice, it would be the GPS. The GHOST is nice because it is small, pocket sized, and moves along with me as I move holes. The Rangefinder is PRICELESS for the driving range though. I love knowing exact yardage when I am working on clubs and distances, and some ranges (like mine) have a grass area for irons only, but a few mats up higher and further for drivers, so the flags are different distances)
I also use my GolfShot app (Plus level membership) and it gives me the ability to track center of green, or drag the marker around to see how far water hazards or bunkers are which is especially helpful off the tee at a new course, or when trying to layup.
Hope this helps! First post!