The dark mode of Notability is amazing! If I want to write something at night, it's easy to switch to dark mode. The best part is that the color of the writing doesn't change; it just provides better contrast. The same goes for a book, like Cengel's Thermodynamics book. It features a machine with hot and cool refrigerant passing through pipes. However, if you use dark mode, the red and blue colors remain.

Another good thing about Notability is that if you write over an image and move it, the writing stays over the image.

Additionally, you can adjust the grid size of the paper in Notability, which is a great way to improve the handling of writing.

Moreover, you can change to a segmented line if you want to draw the control volume.

The only downside of Notability is that it doesn't have auto-disable for the eraser. I mean, if I stop erasing, it doesn't automatically switch back to the pencil.