With the youngest W124 now at 15 years old, you'll have to be picky and discerning when buying on. I found a 95 with only 78,000 miles on the odo. The car has been a joy to drive & own. Try to find one where the previous owner has already done the major repairs: trans rebuild, head gasket replacement, wiring harness replacement. Mine had all those items already done. The looks of the W124 has aged very well, looking neither vintage or new though. The engine performance is still good by today's standard, but not as peppy as cars all seem to accelerate with more pep. My E320 has been reliable and starts up with just one turn of the key every time.
INTERIOR: The interior is well thought out and beautiful. It has just enough flair while simultaneously being utilitarian. The ride quality of this car is very smooth RIDE QUALITY: the suspension is very smooth without being like an old Cadillac. Steering is precise.
No sup much improvements, but quirks for potential buyers to be aware of. The door lock and ignition locks do break. It's best to replace the locks at the first sign of stickiness as you turn the key. Only 15 min repair if caught on time. Other wise, headache once the lock breaks, will take hours.