Hmm, David on several occasions emphasized that the speed will not be the main factor, because that would contribute to farmer centralization. @smacz I would suggest you to check David’s posts on this topic (I am writing from memory so I can’t provide specific links).
If it’s true that all vaults would deliver requests, that would be a disaster. Farmers already don’t get paid for PUTs, so this would mean more work (and precious egress bandwidth) for uncertain gain - cross that - certain loss (if you’re a home user who is fast, you can be pretty sure you’ll almost never be the fastest). With 4 replicas, the average farmer would have to serve 4 chunks to earn 1 coin; all those below average could conceivably store and serve data for free on a permanent basis. Some investment! (If what Seneca said were to be true. Which I think it isn’t.)
IIRC a combo score (“reputation”, which consists of age, uptime, performance, etc.) will play a very important role.
Edit: I found one of previous discussions on this topic here.