I've test driven the diesel the S - the diesel is a great all-round saloon and the S is pretty good as a driver's car. I think the author is missing the point of these cars if he/she/it thinks having a half decent infotainment system shared with another car is of any consequence.
Having driven both I was sooo glad I bought a QP Sport GT - as a driver's car the Ghibli S can't beat its V8 and F1 transmission.
The diesel is great on the move and financially sensible (ignoring depreciation) but you do have to put up with tractor-like vibration and rattles at idle! Don't let that put you off, it has stop-start, so it will only sit idling when cold. It's a good car - try one.