What is the difference between a quad and a plane from builtin Unity?

I am developing for android and using OnGUI with buttons with a texture I read is a bad idea because it draws too much. I created a plane and used the same icon texture with a transparent cutout shader and this looks fine and I can capture clicks from a the same object I was already using before for the implimentation. I read the way to do this is to texture some quads so I ask - Is a quad faster than the builtin plane and which transparent shader is most efficient to use for replacing the OnGUI Button texture?

The built-in plane has 121 vertices and 200 triangles, and a quad has 4 vertices and 2 triangles. As for the shader, unlit transparent shader? - Questions & Answers - Unity Discussions