i have done it. my personal opinion is that overt pressure to *analyze* reduces my enjoyment of the music performance, which defeats the whole point. i prefer conscious listening over time, and see how i react to music i know well played through a tuned or modified or updated setup. i tend to actively listen to music for at least an hour a day, and simply observe my enjoyment level. and then i analyze the reason some. it may have been my mood. it may have been a change. but i can only ABX for 15 minutes then i tire of it. if i have to listen *that* close typically it isn't worth my time. i know what i like stuff to sound like. :)

I must agree with pablolie.
And I also find ABX testing a bit fatiguing , although when I'm doing this kind of test it's not for the enjoyment of music but to learn something about a particular aspect of the sound.

I've always found ABX testing very limited in it's usefulness but never the less it's one test out of many we use to help determine what we are hearing and if it's of some importance.