The 5.5 twin turbo or the older supercharged one? They are generally pretty reliable...they are just a w212 shape E class in a posh frock! I don't like the first generation (like in my comparison)....very odd headlights....the facelift version looks much better.....but as far as dimensions go they are the same.
It was a normally aspirated, 377bhp version pre-facelift. The front reminded me of the original Citroen C5
The car felt quite cheaply made for an "expensive" car.
The air suspension was a bit weird. 90% of the time the ride was superb, but the handling was very dull, and if you hit a sharp ridge it would sometimes catch out the suspension and the shock would transmit straight to the car as if there was no springing at all.
The 19" AMG wheels crack very easily.