Steve has made some very valid points.
I also own a 1989 260E which I bought in 1992. The car now has 245K. I will not say I did not have any problems with the car but overall, it has been extremely reliable and the cost of ownership has not been much greater that it would have been with a lesser car. Problems (and sometimes big problems) will come with any car as part of the standard equipment package.
A transmission problem, although hard to swallow, does not mean the car is poorly built or less reliable than a Toyota. I had a transmission problem on a 1997 Honda CR-V, only about 5K outside the warranty period. Normal? No, probable:Yes.
My Benz has been maintained by the book (and some) is still rewarding me with a ride, safety, comfort, handling I could not find in a lesser/newer car.
I'm on the point of having to decide what to do with my 260E as it is beginning to show some signs of old age. But what can I get as a replacement? Another/newer W124 would be a solution but I am inclined at throwing $5 to $7,000. at it to bring it back to it's original glory. This would be a cheaper/better solution than buying a Toyota or Honda and I would still be driving a Mercedes.