I'm like Beer. Got hired into the ER, then got displaced to the MD88.
Like everyone says, the 75/76 is very hard to beat. With that said, I like flying the Mad Dog. There are no computers or hydraulics between you and the controls. You can close your eyes and know exactly what the airplane is doing. In that aspect, it's a very honest airplane.
The worst thing about the plane are the trips. 5-leg days, 30 hour layovers, and if you're ATL, very little west of the Mississippi (although I hope that changes when everyone converts to the -90). The only good thing about the trips: No red eyes!!! At least not in ATL, although get used to 0530 departures.