I have been thinking of enabling this feature. Aside from this issue, does it make visible difference in terms of performance?
I really wonder why we see the opposite result.
Is the site on AWS? Maybe that's the reason for this.
If your origin has poor upstream connectivity then it might.
We're on our second Argo experiment. So far it's actually made little difference for some locations and significantly decreased performance in others. Definitely not worth paying for... for us.
You can just enable it, test your performance metrics and disable it.
It now properly pro-ratas the $5 and even credits back the remainder of the month if you cancel it from the Billing tab.
And let's you re-enable it. :)
There's really no valid metric that can be derived from a one shot test. Just because the 2nd run with the magic on is "faster" doesn't mean anything. Hundreds of variables could have changed between runs.
Most people use monitoring systems that run synthetics every minute and those are reasonable for an "overview" of trends, but they also don't show you the worst case times that are happening between runs.
If you start getting more granular and monitoring at 5 or 10 second intervals you get to see more real world response times.
On something like CloudFlare the averages (without Argo) are really good, but the max and standard deviation is very high. Hard to beat for $200/month but when you start paying per Gb you should start testing other providers.
No CDN that I have used (and we've used Panther Networks, CDNetworks, Cotendo, EdgeCast, Akamai and Fastly) has ever charged us for ingress.
Usually you pay for egress from edges and whatever is going between the edge and origin.
So it would be good to get that clarified so we know.