[duffmancd]

I've used IronCAD, Solidworks, pro/e and AutoDesk Inventor. If you're approaching 3D modelling as a draftsperson, IronCAD was much more productive. Want to change this part, just do it. Want to specify a relationship, you can but it's entirely optional. It's hard to describe how much faster it becomes. This was particularly noticeable in the hands of our 2D drafties who converted.

But I have also had the joy of trying to program IronCAD. The parametric solver is not as good as the other programs (who live and die by it). I suspect, though cannot prove, that the little automation system we used to create a base design would have been a lot more stable running on a different system. But it was too much work to completely re-implement (and convert all the old designs etc.). So I had the joy of fixing changes between versions by e.g. swapping the direction of a constraint, or hard-coding an initial offset so that you approach a solution from a particular direction.

Also, adding 2D annotations to create a production drawing were painfully slow and finicky in IronCAD.

I think I agree with the author that history-based editing caused the whole industry to go down a less-efficient path, but I also think it's too late to change the past now.