I received this set as a Christmas gift, however it was missing a pen. I contacted Ohuhu support to try to figure out which pen was the missing one so that I could get it replaced. They said that the single pens were out of stock, and offered to send me the 20-pen pack with the missing pen instead! Their responses were quick and their willingness to solve the problem was phenomenal.
The pens themselves are very vibrant and colorful! I've never been good at watercolor so I'm still getting used to it, but from what I've tried the pens are fairly easy to use. If you feel more comfortable coloring with markers than paint (but still love the water color style) I definitely recommend this product!