Hi robains - I've gone from Autocad 10 (ancient) through TC since version 6 I think. I have limited experience with Cinema 4D and other nurbs-based programs, but recently I decided to draw a Dalek from Dr. Who (ok, I have no life...), and I found a tutorial done in Cinema 4D which was an interesting comparison.
As I mentioned in my Gallery post ("Exterminate"),
"Another fun thing was going through an incredibly detailed tutorial done in Cinema4D at http://www.projectdalek.co.uk/files/tutorials/virttutindex.html
It's a nurbs-based modeler, which is incredibly tedious (to my inexperienced eye) -About half the time I'd have the parts drawn in a tenth of the time it took to do in Cinema4D - but then he'd do some complex surface polygon manipulation that was impossible in TC, and there was a lot of time spent trying to replicate nurbs editing with 3d adds, subtracts, slices, etc.."
I think that's one advantage TC has over C4D or TrueSpace etc. The ACIS solid modeling engine is much easier to deal with than tediously editing nodes, lines and facets you have to go through with C4D. If you're modeling 3d objects for usual architectural and engineering purposes, I think TC wins hands down.
If you're modeling creatures, monsters and CGI-type things with lots of irregular non-planar shapes, maybe C4D is the way to go.
I don't know how good C4D is with 2D planar models like electronic circuits, but TC is great for that. The learning curve isn't too bad for 2D - going through the "help file" (which is a pdf manual) is perfect, since they give a lot of good examples. The user interface is daunting at first, but unlike TrueSpace, at least you can easily figure out what things do by hovering over the control - right clicking brings up a handy menu that allows you to easily change between drawing and rendering modes.
As for animation, I haven't tried C4D - have played with Maya (which makes me want to let them sacrifice me on one of their temples) and Flash (which is almost starting to make sense, but it's taken a lot of beer to get that far). With Turbocad, you have to buy the Animation Lab plug-in, which is kinda clunky and primitive compared to Flash, but it has all the basics and would probably do what you want. Animation is very complex and the thing I like about Flash is the ability to embed animations within animations - like if you wanted to move a spinning top across the "stage" - one animation is getting the top to spin, then that "movie" is embedded in an animation that moves the "movie" across the stage. Don't think TC anilab can do that. But $$$... Animation lab can do simple animations that I've used to show data flow through networks so that might be all that you need - check out the gallery samples.
Won't get in to rendering and lighting - I've seen incredible photorealistic jobs done by all the major CAD programs, but haven't seen many reviews pro or con one way or another..
That's my $.02 - hope this helps