Depends what you after!
If you don't need a comfortable ride and had no intention to have the car on 18s, I will spend that money somewhere else.
I had mine on comfort setting 99% of my driving! Even if I use the sport mode on my GTI with 17s, it still rides better than my mother's GTI on 18s without acc.
THE BIGGER WHEELS AFFECT THE CAR HANDLING AND RIDE MORE THAN THE ACC!
If anyone is looking for a Lexus like ride, then they have bought the wrong car...and I agree, the higher the sidewall profile, the more comfortable it will be, at the expense of precise turn in.
I swap from 18" winters to 19" summers and the 18s are noticably less edgy and give a smoother ride...whilst the 19s are noticably 'nicer' to drive at pace as the car just feels more alive and responds more quickly.
I drove a Mk5 GTI on 17s recently...and it felt really wooly next to my Mk6 on 19s.
The bottom line remains, if it's not worth the money to you, don't pay for it.
But the ability to sharpen the handling when I want it, and soften the damping to protect wheels/tyres or give a smoother ride on crap roads, makes it an appealling proposition for me...and well worth the asking price.
Put it this way, if you can have a more comfortable ride than a standard GTI on 17" wheels and the turn in and chassis balance close to the best coilovers with 19" wheels, all at the press of a button...what's not to like?