It looks like the update started rolling out around two days ago, and people seem pretty pleased with it. Of course, Oreo features like Autofill, picture-in-picture, and notification dots are present, as are Samsung-specific niceties like Dual Messenger and high-contrast keyboard options. The update brings the build number to R16NW.G93xPVPU6CRE7.
If you haven't yet received the update, be sure to manually check in your settings. T-Mobile (and US unlocked) users are no doubt getting antsy now.