I hope I'm mistaken about this but my experiments seem to suggest that iOS downloads large files significantly slower than an Android device on the same Wifi network.
For the test I download a 70MB test jpeg file in the Chrome browser on both an iPad Mini running 6.1.3 and a Nexus 7 running 4.2.2. The Wifi network is an Apple Airport Express running 7.6.3.
Android downloads the file in 91 seconds, iOS takes 314 seconds.
I forgot to show it in this video, but the Android version is really there at full resolution if you tap on it.
I've repeated this test using Safari on iOS and it's the same so I think it's something to do with Wifi or the TCP stack.
Has anyone else noticed this?