I know it's still alpha, but I figured you guys were a good bunch to ask.
Thanks and Happy New Years to all!
My initial thoughts:
1. It's dead simple to learn and use. The documentation is excellent.
2. From my experience, it looked fairly ready for production even though it's still technically under beta.
3. I showed a friend of mine (who is an android developer) the android app that I built using jQuery mobile and phonegap - and he could not find out that it was not a native app. Only after I told him, he said that if he were to really nit pick - it was a trifle slower than a native app.
4. But, in my app I created a separate HTML page for each screen, and loaded them using <a rel="external"> - this causes complete page re-loading. I found this more snappier than loading pages using XHR request which jQuery mobile does by default.
5. The transitions are a let down. On HTC Wildfire, they were very slow. I eventually ditched the page to page animation for my app.
I wish they would get better performance wise.