Is Argo worth it for U.S. only traffic?

I turned on Argo on our account yesterday and I’m wondering if we will really benefit from it:

  • All our instances (AWS) are based in the us-west-1 zone
  • 100% of our traffic is U.S. based, mostly coming from CA, OR and NY

From what I read, we could still potentially see a 15-20% performance gain though.

What would be the most accurate way to verify if Argo is really making a difference?