I have not been out more than once since the new Rwy config opened but if 28R is in use, then the USG building is the best place. IF
28C is in use, go to the very end of the street ( intersection of Scot Street and Lawrence) and face north. That is probably your best bet. The aircraft will be practically over your head as they land. Or I have heard that the Schiller Park Metra station too is a good spot, but I have not tried it.
For take offs in that direction, you could try any of the places near Beeline road and York road on the west side. But like I said, I hv not been out recently.
Just curious, what days are you planning to be at ORD