As far as annual software updates go, Sierra is a fairly modest one. Some of the most practical features like Optimized Storage and Desktop and Documents in the cloud, are also the least flashy. Conversely, the additions that have gotten the most attention -- think: Siri integration and Auto Unlock -- don't always work as expected. You should absolutely update to Sierra, but remember: It's probably the small stuff you'll appreciate most.
- Siri integration is useful, if you already use Siri
- Universal Clipboard is handy
- Apple Pay on the web is secure and convenient
- iCloud and storage improvements have practical benefits for everyone
- Siri isn't always smart enough
- Auto Unlock is temperamental
- Some of the best new Messages features are iOS-only