The vendor is Greenworks, who make Xfrog, so they are legit and of good quality. As bruno says, they are very useful for long distance shots where you need a forest, but don't look so good close up. For distant forests they are excellent because they are so low poly.

If you buy the most recent DVDs of Xfrog plants they come with the billboards already included. Likewise if you buy individual plants from Cornucopia, you get the .vob format and the billboard.

Steve