Impresso for Mac/Win comes with the same features as the mobile app, with an ellipse detail tool and the same one-touch presets. What the desktop has over the mobile version is more control over brush styles, brush depth and a larger preview area; it also allows you to edit the En Plein Air artist palette colors to create your own custom color scheme. (This version does not include the Plugin)
Impresso Pro for Mac/Win adds pro layers for blending impressionism styles with brushes to paint on and off the strokes. It has the same ellipse detail tool for rendering small brush strokes over placed areas and supports up to four ellipses per layer. This version also allows you to customize the En Plein Air artists' palettes, but includes a bonus effect called Tache for an ultra impressionism style. With the pro version you get a Standalone Application and a Plugin for Photoshop, Elements and Lightroom.