Originally Posted by
user123
If flying an AA MD-80, you have a 50% chance of delayed at the gate due to maintenance items "pending sign off"

Above is wild exaggeration.
I fly on tons of AA MD-80s as well as plenty of other types operated by AA, DL, MQ, OO... I also track all my flights.
There is no airline/equipment type in my experience that jumps out as having a disproportionate number of delays.
I've had mechanical delays on AA MD-80s... at about the same rate as I have had mechanical delays on other types and other airlines.