Trying the demos on both a Galaxy S and an iPad, I'm struck by how slow everything feels. Buttons don't react when you press them, but a second later, which isn't acceptable when you're competing with native applications. However, it looks good and they have time to fix the speed issues. I might look into using this instead of something heavier, like sproutcore.
I've been using this since the hour it was released, and colour me impressed; the jquery team works _fast_. The amount of improvements in this release are astounding. great work guys!
I coded my first JQuery app (www.quaverly.com) using JQuery Mobile last weekend. It was ridiculous how little time it took to make something look semi-presentable--it would have taken me maybe a week to code the equivalent in GWT, and it wouldn't have looked as nice, either!