It may look broadly the same as ever, but Apple says Yosemite is "completely new", having refined the system "app by app. Feature by feature. Pixel by pixel."
The flat look and pastel colours certainly look fresh, and tie in well with iOS 8. Everything looks cleaner, thanks to simpler icons, streamlined toolbars and translucent elements. The updated system font is also easier on the eye, and everything is optimised to look great on a Retina display.
New features in Yosemite: Today view
Within Notification Center there's a new Today view which gives you an overview of what's happening with information from widgets such as Calendar, Weather, Reminders and even social networks. It's a view that will be familiar to iOS users, and it's accessible by swiping in from the edge of the trackpad with two fingers.
New features in Yosemite: Spotlight
Spotlight now appears at the front and centre of the desktop and includes new categories of results. You can get suggestions from Wikipedia, Maps, Bing, App Store, iTunes, iBooks Store and more.
New features in Yosemite: Continuity
Just as those who own both an iPad and iPhone have discovered in iOS 8, they work better together. It's the same with Yosemite and iOS.
If your iPhone rings, you'll get a notification on your Mac. You can even answer the call and have a conversation, be it audio or video. If you want to, you can make a call from Yosemite, simply by choosing a contact, using your call history in FaceTime or by tapping in a phone number (people still remember phone numbers, right?).
It's the same story with SMS. Incoming messages are shown in the messages app, which looks just like the iPad version.
You can reply to text messages from a Mac running Yosemite; it doesn't matter if the recipient doesn't have an iPhone as the message is sent via your iPhone.
Handoff means you can use any of your Apple devices for a task. For example, if you start writing an email on your iPhone you can finish it on your Mac. If your iPhone is physically near your Mac running Yosemite, this can be automatic. You'll see an icon on the Dock (or on the lock screen of your iPhone or iPad) showing the app you were last using, and you can click it - or swipe on the lock screen - to carry on whatever you were doing. Currently Handoff works with most Apple apps and developers can use it in their apps as well.
AirDrop is a feature that was already present in OS X Mavericks, allowing users to quickly exchange files with another Mac on the same WiFi network. Now, in Yosemite, users can use AirDrop to transfer files from an iOS device to a Mac and vice versa.
New features in Yosemite: iCloud Drive
You can store any type of file within iCloud Drive and the feature is built into Finder so works just like a regular folder. This means you can drag documents to it, arrange and organise them with tags and search with Spotlight. You can access the files in iCloud Drive from Mac, iPhone, iPad or even Windows devices.
New features in Yosemite: App updates
Fitting in with the new look, Safari has been given a new 'streamlined' design which, according to Apple, puts the most important controls at your fingertips. To this end, there's a new Favourites view which gives access you your most used websites and a new Tabs view which shows thumbnails of open pages in a single window.
Improved privacy features include separate Private Browsing windows and built-in support for DuckDuckGo – that's a non-tracking search engine. Spotlight will also chime in with suggestions if you search a common or popular term.
Updates to Mail mean that editing and sending attachments is easier. Markup means you can fill out and sign forms quickly and also annotate PDFs or images from within the application. Mail Drop is a new feature which lets users send large files such as videos or images up to 5GB in size from within Mail to any email address.
Messages also has a new look and provides more options for communicating with friends and family. You can now add titles to message threads so they are easy to find, add new contacts to ongoing conversations and leave any conversations you want to. Soundbites is a way to create, send and listen to audio clips within Messages. As we said earlier, it's all very familiar to iPad users.