I have been using watercolors since 2008 and have to say it is by far my favorite medium.
For sometime I was thinking of trying Gouache paints, curious to see how different they were from my beloved watercolors, I had heard they were opaque watercolors but only had tried the gold, silver and a the very bright Linden green.
I found this Winsor and Newton Designers Gouache Introductory Set on sale at half price at Ken Bromley Art Supplies and immediately order one. It just arrived so I haven't try it properly yet to say much, but I couldn't wait to make a little color chart.
I will tell you more about it when I use them and get to know them better.