me and vibs have used that before last year for our uni project.
its okay, but is missing some bits and pieces, and can be a bitch to properly sort out depth and what plugs into what.
for basic cars made of bricks, its not too bad, cos you can then send it off to lego and they make the kit up for it for you! But for more complicated stuff like mindstorms / technics, its a bit flaky.
theres other cad programs out there for lego too. mikes lego cad (i think?) is quite good, and theres some other stuff that imports into a raytracer , or does some form of rendering as far as i remember - free, as you'd expect.