ArtRage 4 was released couple days ago.
It includes cloner and transformation tools. The other upgrades include square head and more tweaking for the Oils and other brushes. (I don't think all have a square head option). UI customizations and more.
Upgrade is about 25 dollars from some past versions. You can get it on Steam or from their website for about 50 dollars.
PDF that compares features - http://www.artrage.com/files/artrage...comparison.pdf
I have to say the wacom stylus support is helpful.