Painter offers a banquet of watercolour tools. It boasts Digital, Real and Watercolour tool categories, each with a range of brushes. While Real and Watercolour categories require a specialised layer blend mode called Watercolour, the Digital Watercolour will work with other blend modes and consequently tool sets, but it has fewer tools.
I come up with a loose sketch first, flood fill the background layer, duplicate it and set the new layer to either Multiply or Gel. The latter kills the white and gives you a head start on colour. Then simple Water Brush strokes at lower Opacity lay the groundwork. Using that brush, along with the Simple Diffuser, Salt and Gentle Wet Eraser, I work up some tones. I duplicate that layer, then block in the figure with solid colour on a new layer. I then place that layer below the two watercolour layers.
Watercolour-type effects can be achieved not only by applying colour washes, but by removing or working on areas with some of the other tools provided.
The best way for you to choose which Painter watercolour set suits you best is to spend time trying them out.