I've heard it from Unity expert themselves telling you can achieve the same quality (that's why I've included the performance and graphic comparison).

One thing that maybe the "poisoning the well" element is the fact Unity had a generous freemium open doors for hobby developers, which means there's tons of project that are meh while Unreal Engine is well used in creation of AAA games.

Have you tried them both? Is Unreal really that much better for rendering?