How much harder Unreal Engine is than Unity?
Unreal is a much harder engine to work with - but for professional game design - its a much more powerful system. In one job I did, we used Unity to rapidly prototype the game - to be sure is was fun and suchand then jumped over to Unreal for the actual development work. Unity is great for putting together something QUICKLY but for detailed refinement and complicated special effects along with the best possible performance - its not great.