When you say “what is there to compare?”, and also that guy’s addon to Unity was EXACTLY looking like blueprints, you give the impression that you never worked the engine at all. because it is impossible to NOT know about blueprints. You shouldn’t take what I say very offensive or personal though. There are many people that roams around the forums and they never worked on the engine itself. 
And yes, I am not really a UE 4 developer, I didn’t develop anything proper yet. ;D
There is nothing to call both engines rivals. Unity has its own pluses, Unreal has its own. Though when someone creates a visual scripting that is so identical to what Unreal has for free, people can’t help but mention the similarities.
There is a large difference of Unity Store and Unreal 4 one. Unreal forces you to update your stuff, but Unity doesn’t care. Unreal even says that they can help abouıt it if you just can’t update it yourself. So if someone made a 200 USD worth visual scripting plugin for Unreal, I would buy it. But Unity is just a big nop. My 5 cents.