In your system configuration, go to xsengine.ini. Under httpserver, make sure you have a node named developer_mode. Set developer_mode = true. Now any system errors or dumps will be sent back to the browser instead of the standard http 500 generic error screen. I assume this is what you were referring to. In other cases developer might catch exceptions in the code and return those in the response body.
I am curious why you feel the debugger is 100 times slower? I actually like the debugger as opposed to having to trace or output variable values.