Never tried Truespace but I agree with whats been said about Blender. Great to have a free program but I don't think that interface is worth the effort. Blender gets a lot of coverage in the latest issue of 3D World magazine, plus there is a news item announcing v6 of AC3D.
Another program I have been using recently is Cybermotion (
www.3d-designer.com). It costs about £84 and for the money you get a pretty good renderer with photon mapping and caustics, particles, landscape generator, bones, animation, forward and inverse kinematics etc. Only downside is the modelling tools are basic to put it mildly. I imagine it might make quite a good companion to AC3D actually.
Regards
Paul