Lately, after trying ArtRage on my new cell phone, I've been considering the Samsung Galaxy Note Pro 12.2 as a cheap(er) and portable alternative to a Cintiq. While the response of the stylus to the surface isn't perfect, at least I can draw directly on the surface which is the more natural equivalent to pen, pencil, or paintbrush.

So far none of the art programs I've used (on my phone) are ideal, none are that bad. I suspect there's a learning curve beyond which I'll understand which brushes do what so I can lay down exactly the colors/textures I'm trying to create.

The 12.2" screen seems big enough for decent sketching, especially with the high 2560 x 1600 resolution of the display. I'm obviously still going to have to return to my easel for large canvases, but this seems a good way to do color studies and quick renderings without having to commit paint.

Oh, and as an added bonus, you can use it as a tablet.