I have a set of their candies and despite being good to work with I came across 2 major problems, the first and most important for me is the fact that it stinks despite being water based and I can feel it instantly eating away at my lungs even with a mask, and second, anything going over the top of them tends to lift them up even after trying to heat set them, so I'm guessing that if you start a project with these, you have to finish it with these.
This is my experience, but only with the candies, I can't speak for any of their other products although I've heard nothing but good over them and they are very popular here in Holland as mentioned among the modeling community.