Russell, I would really have liked to become proficient in FreeCAD.
I should say to be fair, it didn't crash often. I think I lost some work one time, but at a bad time in terms of overall frustration in trying to achieve a particular goal. And certainly, running old SketchUPs in WINE (a Windows-like program environment for Linux) occasionally crash, too.
If I'd ever found a path in FreeCAD, no matter how difficult, to achieve that flywheel shape, I would have stuck with it. Because I would then have then thought I'd find quicker and easier ways to do that with practice.
At one point in trying to taper an elliptical sectioned spoke, and then fillet that into the flywheel rim I reached a dead end.
It seemed to me that a possible solution was not to do that in the round, but split the spoke lengthwise -- as if making a half-pattern, before tapering it. But when I tried that, the taper was applied vertically as well as width wise, lifting the flat face, which I didn't want.
I kept running into these sorts of problems. I think they are due to functions (like taper) being pre-defined, rather than achieved through applying primitives -- as you do in SketchUP. In the latter, it's easy, just draw a straight elliptical sectioned spoke, rotate to one end, and then scale it's section with grab handles. Which you can do either uniformly or in one direction only, depending on which handle you grab.
In FreeCAD, you often have to fill in numeric specifications and preferences for an action before you actually do it. If there isn't a slot to change some spec that you need, you're out of luck.
Manipulating SketchUP objects is more analogous to manipulating physical objects made of clay. You form or deform them with on-screen tools, then afterwards set the amount of deformation more exactly by typing in a number.
I still regret not being able to use FreeCAD -- it bothers me not to succeed with something I set out to do, and I don't really want to be dependent on just a single old CAD system.