I've been trying out the latest beta of Firefox (4.0b11) which is seeming nice but still has a few little issues (the old no hand cursor issue that chrome had for ages seems to be one of them).
But one thing that was making it impossible for me to work was the timeout crash on the flash player while I was trying to debug.
The default timeout for plugins is 45 seconds which can easily be changed in the about:config page:
- Type about:config
- Look for the dom.ipc.plugins.timeoutSecs
- Set the value to -1
And be blessed with no crash reports for flash debugging. Note however this affects all plugins and operation of the browser, so it's not suggested for normal browsing.