I've done A/B testing with decent headphones (http://abx.digitalfeed.net/list.html) and not been able to tell the difference. Maybe you can, but I'd bet that most people can't, and in any case the result is far from butchery.
A lot of people love to fret about this stuff and convince themselves they can tell for the exact same reasons uninformed people go out and buy $200 cables.
It's also the same as people who install Gentoo so they can tune their CFLAGS to be 0.0000001% faster under certain workloads at the cost of not running on any other machine and crashing inexplicably on occasion.
We all love optimizing things, regardless of the actual real-world benefits.
I've mostly noticed differences in lower frequencies seeming attenuated in electronic bass music, though it is possible that this might be due to mastering (for stream vs CD) or normalization