I own this set, and have only just begun experimenting with the possibilities. The colors are vivid, and once dry they are permament, which is good for me as I'm not experienced with traditional watercolor techniques. My set bought at a retail store came with a 20 minute DVD with helpful hints and tips.
I love that this set comes with an insoluble pencil so that any outlines or guidelines that one has made will not disappear when you add water. Also, I plan to get extras of the black inktense pencil, as it is like having a portable inkwell that won't spill all over my car's upholstery or in my purse. It provides a velvety black as tested on my watercolor paper.
If you love both drawing with pencils of any kind as well as with pen and ink, this set offers a wonderful hybrid of the two. I think it is especially great to add to a traveling art kit. I just think its altogether great.
I can't wait to try Derwent's graphitint line as well.