I have the advantage of having cars from the '50's, '60's and '70's, so will outline my thoughts. This is going a bit beyond the 108/9 vs W116 debate, but may be of interest.
300b 1955 - This is a very big, heavy car, running on cross ply tyres. The engine is a 3Lt 6 cylinder that was originally designed for a fire truck ! It is the same engine as the 300 SL Gullwing and Roadster, albeit with twin carbs instead of fuel injection. It is a 4 speed manual column shift. It feels stately, and attracts a lot of attention. It is not fast by any means, it is noisy, especially when travelling at 70 mph - especially engine noise because of the gearing, but it drives very smoothly and steering (no power assist) is easy, especially at speed. Absolute road presence.
220s 1958 Hydrak - If you have never had the pleasure, and I use this term lightly, this is a very good car to drive. It will (almost) keep up with modern traffic, but the gear ratio's again make it labour a little. Very comfortable at 60 mph, and the brakes (drum) work extremely well for an old car. The hydrak takes some getting used to and you cannot leave it with a valet to park !
220 SEb 1962 Automatic - I am not a great fan of this car, and I'm really not sure why I bought it. It doesn't have the character of the two previous cars, it isn't any more powerful than the 220s, and is to my mind, lacking in personality. Maybe I need to drive it more !
300 SEL 6.3 - One of my favourites. This is a no holds barred, hot rod in a brick shaped sedan. There is not a lot of sophistication about it - except for the mechanicals, but in terms of style, it holds it's own. The gearbox is harsh, the air suspension hard, steering is a little wayward, but that engine ! Accelerate a little hard, and it will kick down to start in 1st gear and you know you are alive. It has extraordinary handling and even though it feels like it would break away at any moment, it is always manageable. Enormous glass area makes you feel that everyone can see you.
450 SEL 6.9 - The difference between the two generations is chalk and cheese ! The W116 is sophisticated, quiet, modern, and you feel a lot more cocooned than in a 6.3. The engine is smooth, almost silent, the gear changes imperceptible and you feel as though you don't really need to drive it like a 6.3. It almost drives itself. The seats are more comfortable, and is generally a much more modern package - but not as much fun !
280 CE - I have always like the shape of the coupes, but there is no comparison to a 6.9. The 6 cyl engine is slow, especially when coupled with the automatic. It is more of a leisurely drive, and could never be considered sporty - even though it was designed this way. Being a W123, they are extremely reliable, capable of huge mileages, and generally feel bomb proof.