I notice the ASL working, but it is subtle. I have a ML system and notice the bass increase as I accel from a stop. I can't remember what adjustment I have it on though.

 

I've noticed it working. It sometimes chooses to get louder when I don't really think it's necessary. That's probably the only time I notice it. Sometimes when I would think it would crank the volume a bit, it doesn't do anything. My observations were that it is perhaps somewhat tuned to your engine noise--but I think I remember being told that it was monitoring some other noise levels.

If it were obvious, like some of those annoying TV commercials that are intended to blast your ears, I would not like it.

 

The ASL works quite well with the ML system however the general consencus is that it doesn't work too well with the stock system.

ML - FM Radio - Sound Lvl 14-16 (never have to adjust unless i feel like a bit more or a bit less rather than because of intruding exterior noises or over intervention of the ASL).

 

I noticed when ASL is turned on, there are small bars under the ASL text in the display (non-nav) that appear. The most I've seen is 2 bars.

 

I don't think it works that well with the stock system. I would say it compensates about 75% effectively when I'm on the highway. This, of course, has as much to do with how loud the tires are as how loud the stereo is. If I was on some nice quiet tires, it might be more like 90% effective.