I'd download a copy and play with it rather than take second hand advice. Cheetah seems pretty easy to use to me, and deceptively powerful for such an apparently simple program.
It's amazing to be able to buy a program with subdiv modeling, IK animation support, HDRI rendering, a good fast ray tracer, scripting, and -- most importantly -- a real non-destructive modifier tree for $129 (or $109). (Oh, and I should mention FBX support, without which I wouldn't have bought a copy.) The only better deal in terms of functionality for the money is Blender (free), but its interface is astonishingly bad (e.g. the left mouse button sets the "cursor" position -- something that is worse than useless, and by default when you create objects they are aligned to the view) and any attempts to fix it are strongly resisted by its community.
Cheetah is also, by far, the most Mac-like 3D program out there (except possibly for Strata 3D and, arguably, 3D Studio Max, which ironically doesn't run on a Mac). I'd say that Cheetah 3D gives Strata 3D a run for its money in usability, overall has a better feature set, runs faster, and is much cheaper (and I've been a Strata user on and off since 1990).
Unlike most cross-platform 3D programs, you can use Cheetah 3D quite nicely with a single-button mouse (very handy on Apple laptops) while most 3D apps become pretty much basket cases without a 3-button mouse.
One huge deal is that Cheetah has a standard document interface. I'm sick of 3D software that only has one global workspace (so you can't have two models open at once, for example).
Another is rich drag and drop support.
Cheetah 3D is not without it usability flaws, but these are relatively minor. I will probably start ranting about them on the forums when I have more familiarity with the tool.
