The qualities will vary, of course, but the bad hutongs can mean 1.) shared outhouse (no indoor toilet) 2.) dilapidated building 3.) communal politics from what I've heard (hutong grudges and fights for example) 4.) poor immigrant families stuffed into a small room

I don't know much about Beijing, but I found a good article on it: http://designhotpot.com/infographic-four-perspectives-to-und...