If battery life is your top priority and you're already on Android, the Galaxy Watch 6 is probably the better choice. The Apple Watch Series 9 has improved, but it's still generally considered a daily charger, especially with heavy GPS use. The Galaxy Watch usually gets a day and a half, sometimes two depending on your usage. As for accuracy, both are pretty good, but you'll find lots of debates online about minor differences. Since you are on Android, the Galaxy Watch will integrate seamlessly with your phone and apps.