I use Mypaint since many years, for graphic palets worskhops with children , and I have just positive feelings about it. Many tools, rather easy to use, and great compatibility with my Wacom. Recommanded.
Checkout MyPaint for illustration. Coloring at least. It's free. http://mypaint.org/. - Source: Reddit / 3 months ago
Do you know an article comparing MyPaint to other products?
Suggest a link to a post with product alternatives.