We rely on a '95 E320 wagon as our primary family/commuter car. I bought it 3 years ago with 67K miles...it has 127K now! It's been absolutely great! We've suffered common W124 issues...wiring harness and very soon will need a new head gasket. Also replaced the water pump and air (smog) pump and just recently it needed new front wheel bearings. Maybe it's me, but these seems like "expeceted" items given the mileage.
This car makes the daily (20 miles one way) commutes in bumper to bumper traffic easy to deal with. It's taken us to Las Vegas, Carmel, Fresno and lots of places in between with no trouble and I wouldn't hesitate to take any long trip with it. I've upgraded the suspension with E500 bits and 17" wheels to improve handling without sacrificing ride quality.
It has plenty of power for family use (ok, yes it does feel underpowered after driving the E500) and returns acceptable fuel economy given the way we drive it.
If I were looking for another wagon, I'd easily choose a W124 over a W210 or even a W211. I'm old school and W124 wagon just looks better to me.