Pro Easy to create custom components
You make your components like if you're using a vector drawing program. Just drop shapes, draw curves, set stroke and fill color. You can use variables to store values, colors and gradients to use in your components and make them a bit interactive. After that, you just export your canvases to obj-c/swift and use them in your projects.
Pro Support for variables and expressions enables a powerful workflow
Variables are values you can store and bind in any inspector property. You can store values (integer, float,…), expressions ("3.1415 * offset - 1"), colors and gradients, you can store and use colors as a global tint and apply that tint to any object. You can create a color based on another color and modify its brightness, saturation or alpha and make shadows or gloss effects.