All things being equal I would go for the SDL. I Love mine Big and 'fast' compared to the 300SD I had. Lots of comfort and lots or room in the backseat. I get close to or get 30mpg depending on how I drive it. Mine has 302K on the original head with no issues (sound of me knocking on wood)

I do not like newer cars due to all the extra electronics they heaped on them.

In your shoes I would take both on an extended test drive do some highway and some city driving and see which one fits you best.

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad