My dad bought my 350 in 1989 for around $24,000AUD, about the same as a new family sedan back then. At 17 I was struck by the unmistakable grill and badge. It's a BENZ!! And I liked the shape. It wasn't until months later I started to notice it's differences eg: like the heavy doors that Nathan mentioned and the ease with which they closed. But I was off to Uni then, no more merc.
FF to 4 years ago, I swapped an '85 Fairlane for the same 350 off my dad, then I started to notice more qualities that set it apart from other cars I've had. It was in poor nic mechanically, was missing trim, but still drove well and was fun to drive, I was hooked and started to delve for parts.
Thanks to the internet, I discovered I was driving a "W116". A year later I find this site. Then, more and more I discover the engineering qualities that BC talks about. That was a very good post Brian!!
The attraction beyond the grill and the badge came after ownership for me. There's no illusion for me of being something I'm not by driving a Benz even though onlookers are fooled thanks to the w116 timeless, classic shape.
But in the end, I agree once more with BC - To me the 116 in its many forms is class-less and the wonderful thing is you don't have to be wealthy to own and run one.