Is anyone using Sencha Touch for mobile development?
I'm playing with Sencha Touch, I have a project up at GitHub. If you're comfortable with ExtJS it will be familiar. The examples are impressive (requires WebKit browser). You might be interested in this question as well.
I've used it only briefly. It looks very good and has a nice array of tools to make pseudo-native apps. One of the larger concerns is the licensing (the inclusion of ExtJS and the requirement to purchase a license to use the software). Now ExtJS and Sencha have merged - so I am unsure of what the impact will be. Also, as for alternatives, Sencha has merged in JQTouch (a primary alternative). See this post for more information
I think currently it is only optimized for safari-browser. I tried in on Android Phone (HTC Magic, Android 1.6) and the examples didn't work.
but it is a beta of course....