Yosemite will have iCloud drive file storage. Google Drive offers 15 GB now so I am curious to know how iCloud will go above Google Drive. Although Yosemite will be free, I think for my Mac-mini, I will not upgrade to Yosemite. Since the install of Mavericks, I have noticed that my mini runs a tad slower and I can only imagine what upgrading to a new OS would do. I will update to Mavericks 10.9.5 when its released in September but stop there. Im just not impressed with Yosemite when I already have plenty of options with Google Apps.
On the other side of the coin, I am a big fan of iBooks Author!!! Its about a half GIG and took about 8 minutes to download. I am currently working on two iBooks. The first one is a film script which I originally created in Final Draft. The second is a Manual for a local radio station. It will be much more fun to watch rather than read a 200-page manual word for word.
I also have noticed that more teachers are using iBook Author to create their own textbook for the year (Look out Follett!). Once the teacher takes the summer to customize their book with text, pictures, videos, graphics, as well as green-screen video of the themselves, all one has to do is update sections when needed. Besides, its much more hip to have a textbook on a tablet then a traditional textbook. One of the fun features is being able to click on a sentence and have a picture or video pop up. This works great in math formulas and in literature. The student can click on the equation example in the book and a video pops up of the teacher explaining it.
Also, tutors use iBook Author to create basic lessons for struggling students in various subjects.