Not better than all of them.
A geo-redundant rsync.net account exists in two different states (or countries) - for instance, primary in Fremont[1] and secondary in Denver.
"S3 even operates at a scale where we could detect "bitrot""
That is not a function of scale. My personal server running ZFS detects bitrot just fine - and the scale involved is tiny.
[1] he.net headquarters