As someone who jumps between mobile and my home PC constantly, the next version of Apple's OSX is very exciting.
Yosemite features what's called "Handoff," which means that you can browse to a website on your iOS 8 device, and send it directly to your desktop computer. The feature also means that calls, texts, and voicemails will be accessible from your desktop.
Handoff is reliant on Apple's relatively new Bluetooth 4.0 LTE support, which means that your computer might not be able to run it. The 2011 Mac Mini and Mac Air should be able to run Handoff, but hardware released before 2011 will not be able to run the feature.
Keep in mind that your Mac will still run the Yosemite update, it just won't include all of its mobile features.