I am not sure when I downloaded this app. But for the past two months I have extensively used it as my note taking app and have fallen in love with it. Notablity is an iPad only app. Truly designed for those who use the iPad as the main note taking device. I think the designers had education in mind when developing it. In imports pdf's from web, dropbox, etc with ease.
The basic drawing shapes are available and you can place the figure on the paper anywhere. Here is a basic geometry diagram that I put together in a few seconds.
I love that I can create a drawing and then be able to write over it, with various different colors and highlighters. This is something my previous note taking app would not do.
I don't like to type my notes. I like to be able to write them. Previously it was difficult to stay in the lines. However with Notability's zoom feature it is easy. In the draw mode (the pencil), if you tap the magnify glass you can zoom in on the bottom of the screen to where the white box is. I can then write, as you get to the green section the white box will move over it's full length. Then as you hit the end of the screen the app will return you to the next line! It is great to take notes quickly during conferences, and students can manage it in class too! I also like the added feature that you can move the box to anywhere on the screen by dragging it or using the icons on top of the zoomed part.
Organization of my notes is a breeze as well I can create folders (called categories) and then subfolders (called subjects). Subjects do not need to be in folders if you don't want. They can be color coded, searching is easy, I can sort by date and alphabetically.
I can access items from dropbox, send various ways email, dropbox and autosnyc to dropbox. This feature is great. Often students forget to back up the data and only back up the apps, with the autosnycing there is no loss of data! It is currently 99¢. Check it out their web page.