they are the last "real" car built in detroit (well, Texas, actually) using old school tech- 2 valve pushrod V8 in a full framed rwd car with a solid live axle rear end. the same chassis was used from 77-96, and it was pretty much the same as the 73-77 Chevelle/Monte Carlo chassis. they are really solid and reliable cars- and they scored the best out of all the car makers in the world on the government crash tests of the day, if that really matters to you. service parts are dirt cheap, and the optispark ignition in the B bodies was upgraded compared to the early Vette and F body units so that's really not an issue in those cars.
i had a 94 Caprice 9C1 (cop car) that i parted out with 227,000 miles showing. the tie rods were worn out and the tranny was toast, but it was a damn good car that got 18mpg no matter how i drove it and would pull really hard up to the 146mph fuel cutoff. and it wasn't even scary going that fast. i've still got the motor, and will find a good home for it some day.
the 94 Impala SS is one of my "gonna get one some day" cars- i like the 94's becasue they still have the old OBD1 computer and a slightly better ABS system than the 95 and 96 models, plus i like the looks of the rear view mirrors better than the later cars. it's easy enough to add the floor shift and analog gauge cluster from a 96 Imp SS or Camaro Z/28 from around that vintage, and they aren't seen as being as desirable as the 96 cars so they are cheaper.