Apple Watch's marketing headline "The ultimate device for a healthy life." is the best of all their current products (in my opinion) and works well for these reasons:

• "Ultimate" positions Apple Watch as the definitive health device in an increasingly crowded segment

• "Healthy life" appeals to holistic wellness rather than just fitness tracking, sleep tracking, calorie tracking, etc

• The simple and direct language makes the value proposition immediately clear

• Avoids technical specifications in favor of lifestyle outcomes

• Positions health as the primary reason to choose Apple Watch over other smartwatches

• While simple, the H1 flows off the tongue and is easy to remember and repeat