-90, 752 and BAE 146 are all top performers in their categories. DL
likes the MD
-90s because they can easily operate out of the hot and high conditions in SLC
. However they aren't good as far as maintenance goes. The first few had electrical problems and maintenance workers seem to hate them. The 738s that DL
went for have a higher dispatch reliability.
-90s were great performers but along with the MD
-11, they still had a lot of small problems. McDonnell Douglas in its later years produced some good planes, but often did some cost cutting and used older designs (the MD
-11 using the DC-10s wing for example) that hurt them. If McDonnell Douglas had been in better financial condition and spent more money developing the MD
-90 as a new plane, it might have been a better fighter against the 737NGs. The MD
-90 is a strong update of the DC-9 series but it was rushed through production and was not perfected before it hit the market in a move to beat Boeing. (Before anyone flames me too bad, I admit this is all speculation on my part from what I have heard.)
If you have never designed an airplane part before, let the real designers do the work!