[siriuszero]

MID/GREEN - 10% softer than the stock suspension
SPORT - Configurable between 10% STIFFER than stock suspension or 10% softer, as it is on MID/GREEN.

Definitely not "brutal", unless you've only been driving Cadillacs your whole life. For me, it's subtle, but noticeable. Some people don't even notice the difference and for some, it isn't stiff enough and they go aftermarket. I got DDC on mine because most of my time is spent commuting on usually uneven Seattle roads or driving my wife and I places, so I can choose to have a pliant (but sporty) ride most of the time, but if I feel like having fun, I can flick it into SPORT mode.

 

[siriuszero]

Just remember, since nobody mentioned this, that the std sport suspension on the JCW is "stiffer" (10% as I recall) than the sport setting with DDC if you go for the JCW. Of course, the sport suspension is no longer available on anything except the JCW. I have no issues with it but my wife would like a bit softer ride on bumpy roads, so the DDC definitely has its advantages. Just remember it won't work on aftermarket coilovers...has to be removed.

The JCW Sport Suspension is 30% stiffer than the stock Cooper S suspension, but as you mentioned, in the US anyway, it is only available on the JCW trim.