The Watch Series 3, which runs watchOS 4 out of the box, seemed to boot up faster. It also has a barometric altimeter. Every time I went for a workout wearing the Apple Watch Series 2, I had to also wear a fitness tracker to count the flights of stairs I climbed. The new Watch, which is zippier, solves this. Also revamped is the music app, which makes scrolling through albums and recommendations much easier. Heart rate tracking in the health app now offers both the peak heart rate and recovery time. One can also set a threshold to send a notification if your heart beats faster during rest.
The updated workout app lets one customise a workout by adding specific elements. The app also eggs you on, based on your activity. There are also some new watch faces, including a Siri one, and she speaks. It makes sense to charge the Watch every night if you listen to a lot of music like I do.
The Apple Watch Series 3 is much ahead of its competitors. While many of the OS updates would be available on older watches, go for this one if you missed the altimeter as much as I did.
 "iwatch")