I disagree, I have been designing with Inventor since it was started, designed many machines, with less than 2% error, accurate to 8 place decimal, if that's not good, I don't know what could be better.Hi,
I'm a dedicated TurboCAD user and have been since V14. It cannot do all the things Solidworks can do but for 15% of the price, for its' top of the range package, it's pretty damn good. One thing I would say is if you want to use 3D modeling, whatever package you select there is a learning curve and the base versions of pretty well all CAD packages don't do 3D very well or very accurately. There are workarounds but you'll soon tire, (ask me how I know), of faffing about using them.
Turbocad is usually shipped with Ken Doyles CAD Fundamentals, a 2D training CD, plus a symbols CD and you can also buy his 3D training CD. I highly recommend both.
No affiliation just a very satisfied user.