Hi Maarten and thanks.
Well, I can not speak for any other CAD program as I do not have any other to compare. I have downloaded other programs in the near past, but was not happy with them. There is a trade off in CAD versitility and 3D and the price points, features, etc. TurboCAD also comes in the Deluxe Version which will still do 3D just fine at a price point of about $130 USD Not bad. I use the TurboCAD Pro Platinum and it is upward about $1400 if I remember. That may seem like a shock, but compare that to AutoDesk at $4000 and also Solid Works at about $5000 (starting and going up fast with add-ons)
To answer your question will be vague as the fact is that all GOOD CAD will have a rather substantial learning curve. I do know that there are plenty of Tutorials Like textualcreations.com of which I learn from that has plenty of youtube videos of how the professional takes you step by step. My very most humble opinion is that any CAD program that is free will most likely be very limited. If you do find such a program, please let me know.
Donnie