>>21507
Depends on the Game you want to make in my opinion. I used both and i think that Unity is more friendly for beginners. Though if you don't know shit about 3d stuff, you are better with getting some experience in a 2d engine first.
>>21512
>>21535
It is true that Unreal has better graphic optimization out of the box and it looks amazing, but custom shaders are for some odd reason very limited, probably because they would interfere with the out of the box in-engine shaders. Because of that, if you want to have the looks of something else than AAA PBR graphics in UE4 you will enter a world of pain.
If you know what you are doing you can actually achieve UE4 graphics or similar in Unity 5, vid related, though you will need to invest time writing custom shaders or get some out of the asset store and learn the theory behind some graphics shit. Out of the box everything in Unity looks like crap, but because you have an empty box, you can fill it and build up however you want, and you can fill it with way more than in UE4, a lot of people who play around with different artstyles actually prefer Unity simply because of that.
But well, both are useful tools with different options, having their own respective pros and cons, so it all depends on the dev to decide which he should use based on his priorities.