Not to discount anything you've said, but some speed tests I've run find a server that is so close to me that it's not really testing 'Internet speed' as it is just the speed of my ISP and maybe another. I don't know what people want from speed tests and it's good to have different ones, just know what you're measuring.
I'm not a low-latency gamer so none of the differences really matter unless they're near zero. I've been streaming video and fetching/pushing git repos that I use since having a 5Mbps connection.
I get download measurements anywhere from 400-800 Mbps, but mostly under 500 Mbps. I have yet to see an upload measurement above 100 Mbps.
This test just doesn't reflect real-world results for my Internet connection.