macOS is back, and it's spelled just like everyone predicted, with a lowercase m and no space. Gone in the new version, Sierra, is any mention of the numeral "ten", Roman, Arabic, or otherwise. The unified branding across four platforms seems to be more than just for aesthetics, as each is now free to borrow or contribute features to any of the others, while still plainly representing specific hardware.
Of course, the biggest feature borrowed in Sierra is Siri (which sets up several tongue twisters). I was filled with dread in the keynote when its first demo returned a result with extra Siri sass.
But the examples on Apple's Sierra preview website are much more reserved, with standard "Here's what I found…" language. And the flexibility of queries looks genuinely impressive. One example, "Show the PDFs in my downloads folder", is a task that I can accomplish quickly enough with LaunchBar: ⌘-Space, right arrow, D-L, P-D-F. But if I had to do that with just Spotlight or the Finder, it would take me far longer than speaking the question aloud. Drill-down search is also brought over from tvOS, and it appears to have access to several types of extended attributes.
Siri doesn't just have different data to search on the Mac, but different ways of presenting it. Any Siri search query can be saved as a bespoke widget in Notification Center. Remember Safari Web Clips in Dashboard? Saved Siri results are more limited in terms of what they can contain, but integrate seamlessly into the beautiful new light vibrance UI of Notification Center. That visual refresh is present in iOS too, and I wonder if Siri widgets will appear there soon. (One of my frustrations with Siri on iOS is the tendency for returned information to evaporate, forcing you to search again or go digging in an app for the results.)
Apart from Siri, macOS Sierra is behaving as a member of the big happy Apple platform family through inter-OS continuity features. The shared clipboard has the potential to save many awkward trips through AirDrop or third-party utilities, and iCloud Drive now aims to be a serious sync solution. But I do worry that these features will make my data all too portable. I don't want every snippet of text I copy from a private conversation on my iPhone beamed to a Mac owned by my employer. If Apple values privacy as much as they say, there should be easy ways to manage these sharing features, and "easy" doesn't mean trying to constantly juggle multiple Apple IDs.
All in all, my first impression of Sierra is positive: it's the most mature member of a cohesive family of Apple operating systems. It offers room for Siri to grow in new ways and will make the Mac experience a key part of the Apple experience. Now we just have to get used to typing its name.