This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
So at least 25% difference (800MHz vs. 1GHz) can be chalked up to the CPU, if not 66% (600MHz vs. 1GHz), assuming that the iPhone 3 wasn't actually used. The latter case would negate the "findings" of this comparison. So while a comparison of a single device running iOS vs. a single device running Android might make sense, this test says nothing about iOS performance vs. Android performance.
I think rather than the merits of hardware or OS, the paragraph of note in this article is the final one. And, there's at least some reason to believe that the real bottleneck wasn't the devices, but the efficiency of the pipes feeding the devices.
My own experience, BTW, has been that the overhead of downloading an extensive AJAX support package can easily dwarf everything else. In my case, simply bundling the AJAX libraries into a single unit and enabling client-side caching meant a full order of magnitude in speed improvement.