The Gear S3 is a bit like a bigger Gear S2.
The display is a 1.3 AMOLED display — very nice.
You can interchange the bands with any normal watch band — giving you lots of accessory customization.
You can also take calls directly on the watch.
It has the typical fitness features — heart rate monitor, step tracking, sleep tracking, alarm clock, and more.
A new feature is using Samsung Pay — allowing you to pay with your credit card via your watch.