A lot of it comes down to preference but personally I feel Unreal has an easy initial learning curve but the more complicated your scope gets the more difficult it is to manage as an individual or small team whereas Unity is pretty consistent in terms of accessibility for small teams or just one person. I'd also say Unity has more widely available documentation and learning material for very specific tasks/issues. Also writing code in C# with Unity's built in methods has a bit more versatility than blueprints in my opinion. These are the reasons I prefer Unity.