I disagee w/ The Bob. I find the 123 seats (if pads are replaced with German pads) very comfortable, firm yet soft if you know what I mean. On long trips they do not bother me. The W124 I bought for my wife, I hate the seats because they are hard for one thing, flat in the center, not curved, and too high. OK I confess, I got the 124 recently for my wife, primarily for the electric seat function! She dislikes the 123 because it takes lot of muscles to move the seats, and they tend to further away from the pedals and she approved of the W124 in those respects.
I like the acceleration of the 124, but can tell you I will not enjoy working on the beast! But man, does it move on down the road! If I had the means I would have a OM 603 engine dropped into one of my wagons!
(Any 124 negatives? yes - I got a look at the PO's service records. Yikes! Too bad he supported the dealer for so long!)
So far we are keeping the '83 300D, its an old, trusted family member, its so darned reliable, I don't think I'll ever let it go!
Dieseldiehard
1971 220 4-spd manual 105258
1979 300TD w/ ’85 turbo engine 292375
1983 300D 239670
1985 300TD 210120
1976 300D (still looking for an engine)
1987 300D – 255K and newest addition to the family!