The problem with passive attenuation is that nobody has yet done it well without a lot of earcup pressure.
Many people find this does their head in, after an hour or more.
Now, aviation is full of hardened hacks who are happy to fly with a leather helmet and goggles in an open cockpit, while working out the next compass heading and stopwatch time with the slide rule, and occassionally popping down to check the road signs. So, many people on pilot forums don't have a problem with having their head clamped in a vice, and that is fair enough, so long as you appreciate that if you take a girl (or indeed any "normal" person) up in the plane a crappy headset isn't to make a good impression...
As well as doing her head in, and if it is bad enough - and many headsets in common GA club usage really are
very bad - communication is going to be not very good.
Every time I fly I hear people on the radio whose communication is clearly marginal, and I am not talking about phraseology.
Bose deliver very good performance, and the downside is that if the battery goes flat the end result is a bit worse than a £300 D/Clarke, but probably no worse than the usual crappy headset. The other 99% of the time, or 100% if you carry a spare battery, you enjoy the superior performance and comfort.
I flew for 2 years with the battery powered version and never had a battery go flat. And the current model lasts several times longer than the old one did.
I am not for a moment suggesting the Bose is good value for money. I think it's a ripoff, and they are cashing in on being the best. What amazes me (as an electronics engineer with a lot of audio circuit design background) is that nobody has yet matched it or improved on it. It can't be that hard to do. I guess that it is not in anybody's interest to bomb the aviation headset market.