OK sure, well look anything you can do to get it to run in its entirety is beneficial to me - adding a sleep or debugging something. Most of the time the HTML is more useful than the stacktrace because it tells me more about the state of the page at that time and in Gaia the problem is most often the crazy dynamicism of pages, ajax, defer scripts and so on. Marionette often goes too fast, before the page is ready. You can find the HTML output or screenshots in the debug folder.