The ABS give the W124 a different brake feel -- almost as thought they are remote rather than boosted hydraulic, if you know what I mean.
There is a sort of numb spot as the brakes apply -- more noticable in some cars than others -- it is always an anoyance for a couple of stops when I get in the 300D or 300TE after driving the other cars. Much softer feel, not like the 220D or Volvo where you can definitely feel the pads hit the rotors.
If the pedal is just "strange" but everything works and it isn't really spongy, it is the ABS.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!