There are two brand new Apple Watches out now, the $400 Series 6 and the $280 Watch SE. Which one should you choose? Well, it kind of depends. (This is not a cop-out, I swear.)
There are a few key differences between them. The Series 6 is the flagship Watch and has a brand new health sensor that no other Apple Watch has. The SpO2 sensor measures your blood oxygen levels, both in a Blood Oxygen app as a 15-second spot check, and also continuously throughout the day and night (if you wear your watch to sleep). It also carries over the electrical heart sensor from the Series 4 and 5, which enables electrocardiograms that are cleared by the U.S. Food and Drug Administration to diagnose atrial fibrillation (an irregular heart rhythm that can lead to stroke or other serious health issues).