Caveat: I'm just a hobbiest. I've never shipped anything, though I have built several projects of low-moderate complexity in Godot.
- Open source: I'm a fan of being able to fix or modify the software I use. Or just read it to understand.
- Free - Godot is insanely polished for a free engine. It's frankly astonishingly good.
- GD Script is great for quickly prototyping ideas
- Broad language support for when you need things to be fast
- Great documentation and tutorials
- Easy things are easy - When I first sat down with Unity it took days to get my first project working. Godot took a few hours. I don't do this full-time. Being able to build something playable on a nights-and-weekends schedule is so great.