> How often is the performance difference between 100 megabit and gigabit internet all that measurable, though?

For doing backups/restores, in this age of multi-terabyte disks, fast network links (especially in the upload direction) are a necessity.

I don't mind some oversubscription, I can work around peak hours, hell, I'd love to temporarily trade away most of my downlink bandwidth in exchange for uplink bandwidth -- average upload speed is all that matters for this sort of large transfer.