Thank for posting.
I have played a little with Houdini 16 Apprentice, but of course the Heightfield output is in Apprentice is limited by the render size limitations of Apprentice and is watermarked, which could be interesting!
By the way SideFX support is amazing. I reported an issue with the Help System breaking and had a reply from support within 30 minutes and a fix within an hour (they have moved the user interface from qt4 to qt5 http://doc.qt.io/qt-5/qt5-intro.html
which is causing a few issues.
Have you tried exporting an Alpine Fractal Heightfield from TG to H16?
I think that it would be difficult to produce an Alpine Terrain in H16, but would be happy to be proven wrong
I tend to think that WM or WC are better choices for terrain creation unless you need a workflow that allows you to repeatedly change the terrain in which case having everything in Houdini would obviously be better.
I do think that as a general 3D package for anyone wanting a low cost
solution that allows you to do freelance work Houdini is really the only option other than Blender.