This is the cool thing with TG2 and as far as surfacing is concerned, I haven't explored it enough. TG2 gives beautifully natural rich surfaces very easily. In Mojo you could get those forms and actually more spectacularly but it would be very difficult to give them that natural rock form look.
Negative displacement is important for the alpine fractal because it can give you totally different results. Try changing the displacement amplitude to -1000 for the terrain. You'll see what happens and to avoid the terrain ending up 1000m too low you can use displacement offset to bring it back up but I'm experimenting with smaller scale surfaces not so much terrain. With perlin, this negative displacement is already provided for in the fractal. If you negatively displace a perlin billows you will get ridges. The perlin mix basis are combinations of these two forms. Perlin is fast rendering and the most useful basis. If you can do something with perlin then it's best but some things you simply can't do, then voronoi is the next most useful and it's utilized in the alpine fractal. It's also what the fake stones use.
