You can see all kinds of images and videos of Clear in action at its website. This one doesn't really do it justice, but still it's better than nothing.
Clear's magic is in its UI, which is a brilliant mix of subtle animation and the simplest gestures you can possibly imagine. Swipe right to complete a task; swipe left to delete it.
Right there, I see a problem. What are the odds that someone will accidentally swipe left instead of right? The odds increase dramatically because there is no confirmation for deletion (and Murphy's Law now kick in).
Pinching the list collapses it - and brings you "up" a level to the dashboard (of sorts): your list of todo lists. Pinch again and Clear pops you up to the main menu.
Pulling down a list creates a new item. Same with spreading (opposite of pinching) two items in a list. Touch-hold an item and you can move it around in the list. The colours auto-adjust, on the premise that items further up the list are of a higher priority.
There's a few other features of the UI, but you get the picture. It's very clever, and I found it insanely easy to use. Fonts are large enough to read easily, and no tappable item is too small for one's fingers.
All this app does is manage simple lists. It does not handle due dates, repeating tasks, priorities, contexts, locations, tags, or any other advanced feature. And it doesn't sync with anything.
Granted these are early days - Clear is only at version 1.0.1 - but there's just so much functionality that's missing, that Clear is clearly not a power user's choice.
I have also added Clear to my giant chart of iPhone task managers.