It mentions 99.9% availability instead of 99.99%, but it would be useful to understand how that is manifested in reality, and what the underlying architectural difference is.
I tried to ask jeffbarr here, but got no answer.
Watch out for minimum file size on Standard-IA: it's 128kb, and if you write a file smaller than that they round up. It's little gotchas like this that can really burn you...
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