I started out on my 3D adventure with Imagine 2 (the old coverdisk). Then I bought version 3 and version 4. Even so, with six interfaces to manipulate, Imagine is a tough nut to crack.
Later, I bought C4D and couldn't make anything out of it. I find the C4D experience very disenchanting. It can produce impressive results, but the interface is quite horrible!
I never tried Tornado, and probably never will reading the above comments. I only dabbled with Real 3D on an old coverdisk, but I wasn't drawn to it at all (excuse pun!).
For me, getting hold of LightWave 3.5 about ten years ago was a revelation! ALL the Amiga mags placed it head and shoulders over all the other 3D software and there were right! It's superb!
I upgraded to v4 and v5 and now produce a website dedicated to LightWave, the Amiga's best 3D package. Check it out and see.
For me, then, nothing but LightWave will do.
Cheers,
JaX