I don’t have exact statistics, but geographic distance tends to have more impact on Argo (on average) at least in my experience. So on an average request a user in Seattle with an origin in Houston will be more likely to be smart routed than the same user hitting an origin in LA and when you roll in international the % smart routed and percentage performance improvement tends to go up. But as a huge disclaimer, my experience is primarily with Cloudflare enterprise customers who often don’t have the same poor/underpowered origin issues that some of our pay-as-you-go customers might have.
That was a really long way of saying ‘it depends’.
In terms of overall speed I think generally:
Origin w/o Argo < Origin w/ Argo < KV < Object already in cache at edge colo