"Under the hood"? Not really. There are a few nifty new APIs – SceneKit, NSXPCConnection, NSUserNotification, the sharing stuff – and the 64-bit kernel (with kernel ASLR) is now the default. Regarding user-visible features, I think there are a couple nice ones:
- AirPlay mirroring is slick, especially in meeting situations
- Document auto-save and versioning are a lot less annoying and more useful
- Improved sharing support can be quite useful in many situations
- Calendar and Contacts suck less
- Gatekeeper is, I honestly believe, a solid step forward in improving system integrity and security
- iCloud sucks less and is better integrated into some system apps
- You are now notified of both system and app updates, and update checks happen daily. I think this is huge for app developers
- Preview has support for entering text in text fields of PDF documents which aren't true PDF forms (this honestly might be my single favorite Mountain Lion feature)
For $20, I think this is a solid "polish" upgrade. There's nothing mind blowing, but there's an incredible amount of polish across the system, with a few truly useful features mixed in. For me? Money well spent.
Out of the box (so to speak), AirPlay mirroring only supports traditional AirPlay destinations, e.g. AppleTVs. I'm pretty sure you'll still want to pick up that app which makes an iPad an AirPlay destination.
* iMac (Mid 2011 or newer)
* Mac mini (Mid 2011 or newer)
* MacBook Air (Mid 2011 or newer)
* MacBook Pro (Early 2011 or newer)
I remember reading that AirPlay mirroring uses the video encoding capabilities of SandyBridge CPUs, but I can't find a source for that now.
Anecdotally, http://airparrot.com really taxes my 2010 MacBook's CPU.
- AirPlay mirroring is slick, especially in meeting situations
- Document auto-save and versioning are a lot less annoying and more useful
- Improved sharing support can be quite useful in many situations
- Calendar and Contacts suck less
- Gatekeeper is, I honestly believe, a solid step forward in improving system integrity and security
- iCloud sucks less and is better integrated into some system apps
- You are now notified of both system and app updates, and update checks happen daily. I think this is huge for app developers
- Preview has support for entering text in text fields of PDF documents which aren't true PDF forms (this honestly might be my single favorite Mountain Lion feature)
For $20, I think this is a solid "polish" upgrade. There's nothing mind blowing, but there's an incredible amount of polish across the system, with a few truly useful features mixed in. For me? Money well spent.