Did anyone else have some pretty terrible results from the speed tester? I was pretty optimistic seeing their sample screenshot - am I missing something? http://i.imgur.com/UwNBGf3.png
So I suspect you might be having that problem in your test.
Regardless of my results, I've gotta hand it to Amazon on a really kickass speed comparison page. That's a great user experience. It immediately tells me whether I should be using this or not from my particular corporate network without requiring me to waste a day or so trying it out.
The accelerated speeds I were getting hovered around 250-300 MBps