Notability in my opinion is the best note taking app out there. Ive used a lot and I'd be amazed I there was an app that was better. I used notes+ for a while but it was a bit fiddly, if I moved the page down I would mark the page, it wasn't easy to draw a diagram, even though the app has shape detection. Drawing a diagram is fluid in notability, your writing, then you choose add figure then you get a canvas to draw on, with shapes, lines and text, the only complaint I have is that you can't zoom out of the canvas so you only have the screen space to use, if you choose the writing block you can zoom but you don't have the shapes and lines which is a bit of a shame. As well as this you have a filing system with coloured tabs (there's different themes you can use) and then there's autosync to Dropbox. All this for 69p (at the time) its a great digital note taking experience, and the closest to using pen and paper I have come across. I don't work for ginger labs just a happy customer and giving my 2 cents. I'd be surprised if anyone can find better!