I set out to find the best drawing/sketching/graphics app to work within the Surface tablet's limitations. To my surprise, it didn't turn out as I had hoped.
Adobe Sketchbook took the number one spot. Coming in a close second was Medibang. Krita did not fare well, nor did Affinity Photo. I had some expectations for GIMP, and they, too, did not pan out. Leonardo and PaintStorm had brief glimmers of hope and ultimately crashed and burned.
Clip Paint Studio has managed to step in and move Sketchbook from the number 1 spot. Although Sketchbook has tons of brushes, Clip Paint Studio has more maneuverability with conceptual drawing and sketching, implementing filters and 3D capabilities. It's pretty reliable for a small price of $25. You can spend $109 for the Manga and animations capabilities, which aren't necessary for me. Conceptual drawing is where this program shines. I recommend utilizing the tutorials!