I think the Apple Watch Ultra 3 is Apple's best smartwatch, with the most features and the best battery life. Unfortunately, I had a hard time getting used to its size and thickness.
Large Watch with a Luxurious Look
The Ultra 3 has a luxurious look, but isn't as bulky as other large sports watches. Combine this with the bright, colorful screen, and you have a truly beautiful watch. At the same time, I had a hard time getting used to its size, even though I have a large wrist. It's mainly the thickness and weight. I felt the watch much more than with the Series 11, for example. I found sleeping with the Ultra 3 uncomfortable, so I took it off at night.
Excellent Battery Life
According to Apple, the Ultra 3 lasts about 42 hours, so just under 2 days. I found I easily got 2 days, even when running. When I wasn't using the watch intensively, I even got 3 days. The convenience of not having to constantly charge it really sets the Ultra apart from other Apple Watches for me.
Accurate sports metrics and an extra button
If you exercise a lot, the Watch Ultra 3 is a good choice. I noticed that the GPS is more accurate than that of the Watch Series 11. I find the action button, which is unique to the Watch Ultra, very useful. It allowed me to start or pause a workout with a single click, without having to navigate through all sorts of menus. The extra-bright screen allowed me to clearly see my training data even while running in bright sunlight.
Unique features for the Ultra
This watch has several "Ultra" features: unique to the Watch Ultra, but not relevant for everyone. The Ultra 3 is scratch, shock, and water resistant, making it suitable for outdoor sports. This is useful for when I finally get around to trail running again, but not essential for regular runs. With the Watch Ultra 3, you can also scuba dive up to 50 meters and climb the highest mountains. That's great if that happens to be your hobby, but if (like me) you only get as far as climbing the Erasmus Bridge every day, it's not much use.
Smart Features
The main reason to choose the Apple Watch Ultra 3 over a sports watch from another brand is all the smart features. The watch works seamlessly with my iPhone. I check my notifications, pay with my watch, control my music, and find my iPhone with the handy Find My feature. There's no other smartwatch that combines smart features, ease of use, and sports functions so well.