I downloaded artrage ages ago and this is my first try using it properly.... and I absolutely love it. The paint effects have a yummy realistic texture, and it also has a great blending tool (not to mention you can swivel and move the brush nicely with the tablet, and moving around the paint causes it to blend too.... like real paint). I still haven't got the hang of all the tools so my first try is a rubbish painting of a photo of a bird in the snow. But that doesn't matter because playing around with artrage is so so so fun. :D I just wanted to gush excitedly about it.
But for its control and editing, Photoshop is still essential for me... artrage just gives me my paint fix without the mess. ;)