Ive had the S20 for a month or two now. Thankfully I haven't experienced any of the issues that have been wrote about so far. In terms of activity tracking, the S20 is a little useless as it only really has a step counter in addition to the golf functionality.
As a golf watch, I think it's brilliant! The battery is unbelievably good when compared to previous Garmin models. I generally use around 25% of the battery during a round, so at a stretch you could get 4 rounds on a full charge.
The FMB distances and hazards are very accurate, as you would expect from a Garmin, and update quickly as you move around the course.
The auto-shot tracking is decent. At the beginning of the round you select whether you want to track clubs or not. If you do, after you take each shot it will ask you to pick which club you hit from a drop down menu. It automatically registers when you take a swing. I don't know how it differentiates, but it does not register if you take a practice swing. At the end of the round you can log in to Garmin Connect either online, or on an app on your phone and review your round. You can see the all the shots you have taken plotted against the course, which is quite cool. If you've tracked your clubs, it starts to build up average distances for each of your clubs.
if I get the chance later on, I'll upload some screen grabs if you like?
As a golf watch I'd highly recommend it, as an activity tracker, don't bother!
