It works well, except when you have to deal with a really mobile specific stuff (e.g. -webkit-min-device-pixel-ratio, -webkit-text-size-adjust) then you're left with no choice but to debug it on actual device (or in a simulator) although using Firebug on a small screen device is really awkward.

WebKit Remote Debugging[1] would be an ideal solution when it lands. For the time being, weinre[1] looks like a good (stopgap?) solution.

[1]: http://www.webkit.org/blog/1620/webkit-remote-debugging/ [2]: http://phonegap.github.com/weinre/