Hi Andreu,
I've been playing with hypershot for the last few days. Aspects of the interface are actually pretty crude (e.g., positioning objects in the scene can apparently only be done by changing numerical coordinates, rather than by dragging the object with the mouse). However, the materials are very nice and it does a really good job of rendering CG objects into a photographic scene. It's also designed very much with photographers in mind and is easy to use (at the cost of some flexibility). If I was shooting cars professionally (which seems to be its main area of application) I'd certainly want it because of the speed and ease of use.
The good news for Cheetah 3D users is that you can get very similar effects, albeit with quite a lot more work and some post-processing. Once we have a new materials system I think the gap will actually be quite small, which is amazing considering the enormous price difference.
I enclose a couple of examples. The mini on the rocks was rendered using C3D and some post-processing to mix the car, shadows and backplate. The mini in front of the white house was rendered in hypershot.
Cheers
Guy