I'm not usually one to complain, but a lot of the features that Apple has listed about Mountain Lion on their website don't seem much like 'real' operating system upgrades: iCloud - Personally I don't use iCloud much, but I was under the understanding that all that iCloud stuff was already available on Lion... I don't get what's been added to iCloud with ML. iMessage - It's a nice feature, but it's more like an IM client app rather than an operating system feature. You should really be able to get it on the app store in the form of a messages app. Reminders & Notes - These are really just apps, not OS features at all. You could download apps on the app store that could do exactly the same things as these apps branded as OS features. Share Sheets - Again, it's just a feature in many ML apps. Not really part of the OS. Gatekeeper - Seems to me like a way to try and start walling OSX off... Not sure how many people would find this useful, let alone it be an incentive to upgrade their OS.