As part of your question you noted that it seems everyone in 3D Art Showcase & Critique uses UE4 to showcase their work, and you'll find that it's largely because as an artist in UE4, you have a lot of control over your materials that you just don't have in unity, without using either a plugin(normally purchased), or…
I think quite a lot of studios are using it, Im generalising but I think its mostly mobile or f2p games, so maybe its less about the shiny prettyness that ue4 offers but it is capable of that. It is a bit easier to get pretty results from ue4 than it is from unity in my opinion and thats why artists like using it, at least…
Is there an example of a good looking (modern) unity game. It just seems like everyone in 3D Art Showcase & Critique uses UE4. You would think it would be 50/50 in this forum since unity is really popular in general. In most gamejams there is a huge bias towards unity.