I'm interested in what engines you are using and why you are using them. Especially the last bit would be interesting for me, so feel free to comment! Why are you using your engine of choice? Any clear advantages over other engines? Or is it just the one you started with and there was no need to switch?
I am mainly using the Amethyst engine. I am building my game as a hobby, and I want to get more proficient at using Rust. Also, Amethyst puts together all the things I want to have (multiplatform, ECS, Vulkan, etc.), so it's a perfect match for me! On top of that, it's FOSS, so I am very flexible and can decide at any time if I want to sell a game or not. The downside: Amethyst is still very alpha, so expect API changes all the time.
If I had to use a stable Engine, I'd go for Godot. I know that at least Karroffel is collaborating with the Amethyst team and both projects profit from each other in one way or another.. Godot provides many features and good performance, while supporting languages for good performance, quick prototyping and anything in between.
I know that UE is used for AAA and indie games, and it has a good tool suite, so many studios list UE experience as a job requirement. What I don't like about it, though, is the license. It's ok for opensource or free games, but as a hobbyist, selling games is too much hassle.
Unity is also a great engine, though mostly used in the indie scene. It has a similar problem like UE, though, so I don't really want to use it.
Bottomline: For me, it's easier to learn one engine well, donate money and then release all kinds of games (FOSS, free, commercial) instead of going through long licenses and contract details which vary from game to game - or even worse, change the platform based on the type of game I want to create.