It's great time saver for scratch building. If I need a support for a prop shaft in a circular hull, a couple of measurements, a couple of minutes on 123 and in an hour or so I have the exact part.

Flip side is I wanted to print out a model of the Discovery One from 2001. Just the round piece of an existing design online, scaled to 50% which means it was a 5" ball. I had to split that in half to avoid all the support material, then print. To print a half 5" ball with detail at 100 microns....11 hours. That's what I mean about being realistic. 11 hours and at anytime it could go south if one layer doesn't adhere or the filament gets hung up unspooling. And I guarantee it doesn't screw up in the first 8 hours, but waits until it's almost done. And on top it that, the finished print will still need a ton of work to get it smooth.