OK, just had a play with it. It is kinda more technical then the in built Bryce Terrain Editor and I think it would suit Terragen users more Bryce users because terrain creation seems similar to that I remember in Terragen.
I think the Bryce Terrain editor, well specially that of V.6, is easier to use for most of us Brycers,  but those who have used Terragen will feel more at home.