Here it is--I own a 1995 E320 (m104) Wagon, and have a good friend with a 2001 E320 4MATIC wagon (210) It now has 51,000 miles, purchased with 39k on it. It has MB-TEX, no wearing on the seats. Overall, it seems to be a quality car. Like the post above said, the m104 engine is very nice, with good (well very good) power and 26mpg on the highway. It is 3.2 liters, 24 valves, twin cams, aluminum, and about 220hp. Runs great. BUT-it has a leaking headgasket, and I guess this issue was not sorted out until 1996, when of course you couldn't get a wagon. No problems with the a/c, but a vacuum problem with the climate control. Driver's window reg currently broken. The sunroof operates silently, but just recently sticks a little before opening. The 210 wagon has the 3.2 V6, 3 valves per cylinder, 222 hp, but from what i gather from the friend it is smooth as silk and has a great powerband coupled with the 5-speed auto vs the 4-speed auto of the w124. I know that with mine it is a little sluggish off the line due to tall gears, whereas the 210 is quick. However, once above 3500 RPM, the m104 pulls like a bear. It has a very long life expectancy, too, more so than the V6. If you are concerned about luxury, most 210 wagons have leather, digital climate control, some digital guages (newer ones) and a better stereo, a glass moonroof, more automatic features, etc. By the way, wagons stopped in 1995 and resumed in 1998.

In my final opinion, the 124 is the best choice. It is much more similar to what you have now, and is a nice highway cruiser. I actually like the styling of the 124 better than the 210. It should in the long run be more reliable, and is more user friendly. However, don't get me wrong, the 210 is a darn nice car too.

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro