In short: buy it.
If you have time:
When I was searching for a GPS watch, I considered many brands out in the market. After many reviews online, videos, looking for anything that would fit my needs, I chose this watch. If you are essentially a runner, and want a stylish, comfortable and reliable watch, this is the right choice.
First thing you should want in a running GPS watch is what? Well, GPS. Accuracy. Since some runs have sharp turns, or you are in urban areas, that is a must. And in this case, the Forerunner 645 Music is top notch. It supports GPS, Glonass and Galileo.
RUN. Now, moving along to the features for RUN. You can have basically everything you would need, customized intervals, race against a previous time, goals, etc. You can customize even the data screens on the watch, that is, choose what is going to show in the screen while you run, in a very simple way, you can clog in any data you want or keep it clean. After an activity, you can see how well you performed. You have a "training status" screen to show your progress and how hard you pushed, but, MOST importantly, it shows you when to rest - avoiding injury is a top priority!
- Also, you can pair HR sensors and HRM-Run to have the running dynamics suite of data.
Navigation. In this watch is also good . If you build your routes through garmin you will get turn-by-turn navigation (aka breadcrumb trails). The watch tells you when to turn. It is very helpful. The mapping is not topographic, which means you have to create the route first and the screen will show a white line over a black background. It is fine for me.
The Watch. The weight, size and bands of the watch are perfect. Sometimes I even forget I'm using the watch! That means it is perfect for activity tracking, and sleep also. Have I mentioned is stylish?
Battery. The charge is super fast. Great point on that. Although, the battery is not outstanding. The size of the watch enters into play here also, it is a compromise but I am fine with it. I usually run 20Km to 50Km a week, and I charge the watch every 2 to 5 days. But that's only because I don't like to be with battery lower than 30%. Honestly, it doesn't affect my routine at all. You maybe charge during shower, during breakfast, any time. 20 to 30min will be enough.
Garmin Pay. Well, there's still an availability issue here. Where I live now, they are widely accepted. My former town still lacks this feature. Let me tell you: it is amazing. Definitely stands out against the competition and it is very useful. I cannot stress it more.
Music. Well. It's nice. I don't use. I really tried to run with music but the dynamics of the running and the tumbling, anyway, I don't like, and I prefer to listen to the surroundings. Now, if you are just walking, it is a nice addition. But a HUGE problem is the battery life using music. It is simply not good. But then again, they are true to their words and that is very well advertised. You know what you're buying.
Downside. I wanted to train with lactate threshold HR, and this watch can only determine this data with chest straps. I really don't like to use them. That's the only caveat. I'm sure they wanted to be as precise as possible, but it should have as an option. It is possible with software tweaks and push through updates.
- So as a suggestion for the next series of this watch, I would like just to have the option for sea water swimming, an increase in battery life and the ability to perform LTHR tests without the straps.
Nevertheless, this is considered a high-end running watch. For the runners out there: definitely consider this Forerunner 645 Music. Recommended, not even short-list, buy it.