Paul has done a great comparo report on the sedans, but this is more of a different look.
The 210 takes a LONG time to get up to normal operating temperature, and has a very odd result,,,, the engine throws off NO heat. I always raise the hood when I get home in the garage, especially in the winter, and the 400E, or 320 wagon, or SL will raise the temperature in the garage anywhere from 2 to 5 degrees. The V6 in the 210 radiates nothing,, I don't even bother to open the hood any more.
The 210 suffers from the same suspension ills as the 124. Plan on changing sway bar links & bushings at 60K.
Rust. I took the car apart as soon as I got it to the shop and was saddened by all the rust I found. Took me a week to address it all and would have charged a customer around 2 grand to fix what I found. I'll take another good look in the spring, and if it has progressed much further, it's gonna be history.
The motor. It rips and is just a tad slower than the 400E. The tranny probably has a lot to do with the performance,,, love the tranny too.
Worst Benz I have ever had in the snow. I usually turn off the traction aid so I can get up the driveway. I put good snow tires on all four corners of all the cars, but the 400E and my 124 wagon will pull away from the 210 easily. I hope to find some narrower 16" snows next year and stud them and hope it makes a difference.
Really like the interior and the handling and ride. I very seldom push it to the limits, so I really don't need ultimate handling,,, the SL satisfys that need.
Steering wheel controls are neat,,, one example of newer is better.
I really wanted the heated seats, and memory seats which the 124 does not have, and everything is working great so far.
Had to change the front electrical connection on the tranny as it was a gusher. Easy, quick, cheap fix.
Now this is anal, I know, but the engine gets dirty a LOT faster than on the 124's. I always clean under the hood when I clean the cars, and am really amazed at how quick the 210 gets filthy.
Love/hate the wiper system. It has the rain sensing option and when it works correctly it works great, but sometimes it just runs amok, and won't shut off. I'll take the old system thank you.
Wish I could find a good spoiler for the rear hatch,,, the rear window gets dirty REAL fast, and a good spoiler might keep it a lot cleaner.
Took me a while to figure out where the cassette player is,,, I don't read manuals as I should.
The CD player is a lot more sensitive to bumps in the road than the other three cars,,, I mean a LOT more.
The spare tire and wheel is a temporary full size unit. It looks great but says it is for limited use.
The cargo cover is neat with the option of allowing it to just slide up for access instead of having to retract it as in the 124. I had to jury rig the catches though, as it would slide up as you drove down the road and block your rear vision. They could have done a better job there.
It looks like putting a hitch on the 210 is going to be a PITA. The 124 was relatively easy.
Looks are a tossup in my opinion. I still love the looks of the 124 wagon, but the 210 just needs something. I have tinted the rear windows and have 97 E420 wheels on it. There is a silver 210 wagon on the forum gallery that really looks good. He put 18's on it and different bumpers and side skirts. I will put the monoblocks on it in the spring and probably lower the front a bit.
The 124 had some issues over the years, but all in all is a great vehicle,,, time will tell with the 210. If I can keep the rust at bay, we'll see in the long run how it compares.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K