I have had a few different GPS running watches. One was powered by Tomtom. The rest were all Garmin. This is my favorite, to date. I picked it up last year on Prime day when Amazon had it for like 50% off. The beauty of the Garmin 645 Music, is that it pairs with bluetooth headphones and I can listen to my Spotify playlists without having to bring a phone with me. This is also the first Garmin that I have owned with a built in heart monitor. Heart rate has been a fun new metric to track. The watch has all of the regular smart watch functions as well for those who want to get alerts on their watch, count steps, etc..
As far as the GPS system is concerned, it works the best of any that I’ve owned. When I have GLONASS enabled (this allows it to talk to the Russian satellites as well the GPS satellites), I rarely have to wait more than a couple of seconds for the GPS to link up when I start an activity. I use it predominantly for running. But when I was recovering from surgery I used it on the bike quite a bit. It has also been fun to wear on some hikes that we have done here in the Catskills. The only drawback is that the battery life is not great compared to other models I’ve used. But I don’t mind charging every couple of days, so whatev. It is an awesome device that I have really enjoyed using.