>>A pain in the bellybutton to learn though, as it has a rather odd interface.<<
I didn't find Blender too bad. I did a quick walkthrough and then played with it for about 4 hours. I've never, ever done anything in 3D before (unless you count AH Terrain Editor:)) I think it would be pretty easy to make basic shapes, fueltrucks, building, etc. I can't comment for more advanced/precise uses. Also, i'm completely ignorant of the features Hitech has requested.
Basically, all i'm saying is: if it's good for you, then don't let the interface put you off, HT. If we can handle the TE, then we can figure Blender out.