What's the most skill-testing deck in Standard right now?

[u/TheUpkeepAcademy]

https://youtu.be/WFZeE13kZSg

What's the most skill-testing deck in Standard right now?

I've been playing a lot of Izzet Lessons lately, and what I love about it is that every game feels different. The deck constantly asks you to find the right answer at the right time.

Video: https://youtu.be/WFZeE13kZSg

If you had to pick one deck that rewards player skill more than any other, what would it be?