Is the ratio similar to what you'd find on a 2x-setup?

Yes, the ratio is roughly equivalent to 53/36, 50/34 or 48/33 chainrings (the hub has two speeds). In Direct Drive it is 1:1; meaning the cassette and hub have the same speed. In Under Drive it has a ratio of 0,686, which means that for each revolution on the cassette, the wheel rotates 0,686 revolutions. We call this 0.7. Under Drive effectively replaces the smaller chainring on a regular 2x-crankset.