this was drawn in ArtStudio for iPad. The finishing halftones were added in Photoshop. This was for some promotion material for Suzhou a friend is running.

I chose artstudio as it lets you make images in higher res than screen (Not by much 1024x1024), and the client wanted a square image. ArtStudio has the most tools on iPad for this type of things, and the recent update has made it lag less, and let iTunes read the files like sketchbook. Nice, but Photoshop don't read .dat so if you want .psd files you still need to e-mail yourself.

As interface and speed go, sketchbook is still best to jot down some Ideas and Brushes is best for finishing touches.