DC-9's,MD-80's,MD-90's and 717's belong to one of the most successful airliner families ever made.
If the numbers for the whole family are added together,only the DC-3 and 737 have been built in larger numbers.
All these planes are a delight to fly,both as a passenger (if you are seated a little bit forward of the engines) and as a pilot.The cockpit is so quiet that we in SAS do not have to use headsets during flight.
The MD-90 with it's fully hydraulically operated elevators and V2500 engines is even better in most respects.It is probably the quietest airliner around.
"Luck and superstition wins all the time"!