Pros and cons of a 400E
Pros: W124 classic chassis, looks and power.
Cons: (Let me be VERY CLEAR about the following comment: to me it is NOT a sensible issue, but I found out that for some other people it really is a big CON about this specific model, so you may want to consider it or not (it's really up to you): all 400Es sold in the United States were assembled in Mexico.)
For some reason MBUSA actually denies this fact, or it is in complete denial about it. In Latin America there are some rumors that the built quality of the Mexican assembly plant is much inferior to the plants in Germany, hence some "experts" blame many "build quality defects" inherent only to the 400E to this issue.
It is a matter of geo-politics: if someone wants a true Mercedes-Benz they want it to be made in Germany. And the build quality issues maybe a indirect correlation of the problems many Volkswagen models have when manufactured in Mexico. Who knows? I, for sure, don't!