Well, anyone who buys a Nexus 7 without at least test-driving an iPad is a fool, but anyone who buys an iPad without at least test-driving other tablets is really just saving time.
But most smart shoppers will test drive both before buying, and what happens when they do that?
Scroll on an iPad, and then scroll on an Android device. The iPad responds immediately, and the ballistics are gorgeous; highly intuitive. On an Android device, the response is slow, and the ballistics are not as elegant, to put it mildly. Apple treats the entire screen as a vector image, while Android seems to keep the info for every item on a screen as a separate entity, so a screen full of icons scrolls immediately on an iPad, while Android has to crunch and think about it. And that is just one of many aspects of the UI.
But that singular elegance of user interface alone should keep 95% of those who test drive both in the iPad camp.
Negatory, you're thinking of older devices. The latest android devices are buttery smooth and responsive. That old mantra that android devices are slow and unresponsive is just not true anymore.