Decided to put this to a proper test the other day when I found a deserted straight road up in the peak district in dry conditions.
Long story short, D mode offers faster acceleration off the line than S mode. I noticed that in D with about 75% throttle pressed, it's off the line quickly and through the gears well. Any more throttle sees traction control reigning things in.
With S mode, I find it seems to bog down a bit off the line and is hesitant. I assume it's changing into 2nd very early before its got rolling properly. Once on the go, there's no doubting the turn of pace difference as it holds onto the gears longer but just that initial launch is definitely quicker in D.
Don't know if anyone else has noticed it?
17 plate 1.4 TSI SEL DSG estate.