OS X 10.10, aka Yosemite, sports a more modern look and bridges the gap between Apple's desktop and mobile devices. The new Continuity helps you hand off tasks from iPhone to iPad to Mac, but that feature and Yosemite's updated hardware requirements, such as Bluetooth 4.0, push you deeper into Apple's ecosystem. Pros Beautiful but familiar design: Launch Yosemite and you'll appreciate the familiar, easy-to-navigate interface, modernized with flatter, iOS-style icons. It's the same Mac experience, only sleeker. Better notifications and search: The once disdained notification bar has become incredibly useful. The events and notifications bar slides out, like iOS 8's, with customizable, drop-down widgets, revealing the native Weather, Calendar, and Calculator apps. Spotlight search pops out and lets you launch apps, find files and folders, and even search the Web, similarly to the popular standalone app Alfred.
Continuity is amazing: Sharing photos and videos over iCloud is as easy as dragging and dropping. Airdrop lets you transfer files directly to your iPhone or iPad. If you own an iOS device that can upgrade to iOS 8, Handoff (aka Continuity) is a must-have feature. Make calls on your Mac, send SMSs to non-iPhone users, and finish documents and emails begun on your iPad from your desktop.
OS X 10.10, aka Yosemite, sports a more modern look and bridges the gap between Apple's desktop and mobile devices. The new Continuity helps you hand off tasks. Apple - OS X Yosemite - Overview at the Wayback Machine. Which had preceded the release of Mac OS X v10.0. Yosemite is part of the OS X Beta Seed Program.
Fluid and fast: In our tests, the overall OS experience was fast and functionally stable, with most apps launching quickly and acting responsively. Additionally, Spotlight makes search much more intuitive and effective. Cons App incompatibility: Certain apps don't work with Yosemite, including enterprise applications like Cisco VPN, Parallels, and VMWare Fusion, which will not operate properly until updated patches are released. If you rely on your machine for work, before you update your OS, check with your IT department about whether critical software is compatible with Yosemite. Steep hardware requirements: To get the most out of Continuity, your Mac must be running fairly new hardware, the most important being Bluetooth 4.0 for the coveted Handoff feature to work. IOS 8-compatible devices are also needed for mobile-to-desktop connectivity.