I've had a few cars with adjustable dampers and they held some common attributes, keep in mind all were on go fast cars which probably makes some difference in the tuning compared to what might be done on a performance sedan. None of them were soft even in the comfort (by whatever name) setting. None of them felt particularly different going down a smooth road when switching rates. All of them were much better over expansions joints, potholes, a lot less banging around. All of them made the car quite a bit more forgiving on the road while flogging due to the ability to handle suddenly encountered uneven road surfaces better.
An example would be I regularly go up the same on ramp onto the freeway, you take a somewhat tight corner at the beginning of it which eventually aligns with the freeway and heads uphill along it where you merge into traffic. Right in the middle of that turn in the beginning there is a place where the freeway sections don't align and you drop off one and onto the next. Like anyone else I often enjoy assaulting freeway on ramps when traffic allows and that drop off would get the car to take a sideways hop, a scary hop under power. Done it hundreds of times. Enter adjustable dampers and all of a sudden that hop became a lot less scary and I could pull more Gs around the corner. You run into scenarios like that all the time on the road and I imagine every one here can picture there own versions of it they drive over every day.
So you have two things adjustable dampers give you in my experience. On smooth roads your car wont feel much different but when you get into the rougher stuff you start to see them shine as they do a good job of taming the hits. They also handle road irregularities while flogging much better in any setting and allow you to drive with more confidence.
Over on the M3 forums I once mentioned that I had my M mode set in the softest damping position because it handled rough road surfaces better in that setting and I would then manually turn it up from there if I knew the road was good. I expected to get some (mostly good natured) ribbing for my lack of manly man car set up but it turned out the majority of people that responded did the same thing. Another general thing a person notices on the various forums is that where the option is available people who put a check in that box rarely talk of regretting it. You will see some say they will never own another go fast without it. Some will say that getting it turned what they expected to be their fun car into their daily driver. The response is nearly always enthusiastic with as few "meh, wasn't worth the buy in" people as you are going to see when discussing an options value.
Personally while I cant say I wouldn't own a car without it if the box is there I put a check in it without a second thought.
