I had a go of it. It has some very nice elements to it. Two things that I really missed though:
- The ability to load your own palette files
- The ability to shrink the canvas to a particular size?
A number of things lack tooltips, so I didn't really know what they did.
Also it seems like I can only select a new brush size from the buttons under the palette if I click on the paintbrush icon first?
More control over palettes in general would be really good. The ability to move colours around on the palette, the ability to mix two colours, to sort colours based on value, popularity, saturation and hue. Also shortcut keys for navigating the palette, (maybe numpad arrows?).
Also the dark background around the canvas should be something changable, or at least more neutral so as not to throw off colour perception.
Over all, though, it's pretty sexy.