Painting with Yupo paper is totally different from painting on watercolor paper. Yupo is a plastic substrate - it's nonabsorbent - so when you put watercolor on it, it does not soak into the paper. You have to wait for the water to evaporate before the painting is dry.
The biggest plus I found so far is that you can keep changing your painting... over and over. Make a mistake and just wipe it right back up. No problem! if it's already dried, wet it a little an then wipe it up! Or dampen a clean brush and pull up small sections or lines of white. Wow!
Also, since the paint sits on top of the paper instead of soaking into it, it gives a totally different feel to your work. I am loving it. Below is a painting I did recently which I'm calling Rainy Day Poppies. I started out with a drawing of the poppies and then did a colorful under painting. Once that was dry I came in and painted the poppies with lots of paint and little water. After that dried, I misted water on the poppies and let them run. I'm totally loving the effect.
One thing to note, since the paint can be reactivated over and over by adding water, it's important to seal your finished paintings. I'm trying out a few different products but probably a clear archival fixative spray will be the best option.
Pictured above, "Rainy Day Poppies", watercolor on Yupo paper.