Sorry, but to me a landscape with NO plants, NO buildings, NO anything but mountain shapes and water, is anything BUT realistic - regardless of how good the textures are. Granted, Terragen does very good mountain shapes, and has good textures, but even old Vistapro was very good at doing mountains, even though it was very limited in textures. I have Terragen and have played around with it a few times, but I prefer to use Vistapro and my paint program to sculpt terrains for use in Bryce - results in much finer control over details in the terrain. When they are close to what I want, I then import to Bryce for final shaping (erosion, mainly) and texturing. As far as what can be done in Bryce, I have yet to hear of ANY 'type' of scene that can't be done in Bryce.