Data rate between 10MB/s and 2 Gb/s.
Perhaps it's more useful to people who are constantly traveling, but for someone who isn't, I guess I just don't see a point in it. Would I turn it down? No. Would I pay more for it? If it's greater than 2$ more, no. Slow charge is "good enough" in my eyes.
I don't use it a lot, probably once a month on average. But the times I do it's invaluable.