I was with Arccos until my subscription ran out. The system is really awesome, but I wasn’t willing to pay 100 EUR a year.
Tried most of the GPS-apps currently available on the Appstore: Golfshot, TAG Heuer, 18birdies, Hole19, SwingU, The Grint, Fore, HelloBirdie, mScorecard, TrackMyGolf, GolfLogix, BirdieApps - probably some other I don’t remember right now.
I liked GolfShot very much, and was subscribed to Pro, until one day it stopped working, and I would never get it back running again. I could start it up on my phone, look at my watch, and all it would show was 999 yards to everything, without any further interaction possible. I would then have to force close the app on my watch every time.
Decided between SwingU and Hole19, and then went with H19 for a year, and so far it has everything that I want/need: Scoring via Apple Watch, auto-change of hole when walking to the next tee, choice of scoring/no scoring/shot-by-shot. GPS distances are mostly in line with what my buddy’s Garmin S60 says.
At the time I subscribed you also got access to some video content on Skillest as a bonus, though I don’t know if they do grant that still. Also their customer service was really nice and quick and helpful when I contacted them.