iTunes vs iTunes Plus: an audible difference?

With the arrival of iTunes Plus and DRM-free 256kbs AAC files Maximum PC decided to put the higher encoding rate to the test. Running a double-blind experiment with ten subjects and both Apple's included earbuds as well as high-end Shure SE420 canalphones, the results were disappointing. Overall, while most of the subjects did prefer the higher bit rate encoding, "there wasn't a tremendous distinction between the tracks encoded at 128Kb/s and those encoded at 256Kb/s. None of [of the subjects] were absolutely sure about their choices with either set of earphones, even after an average of five back-to-back A/B listening tests."

Personally, I'm skeptical. I listen to quite a bit of classical music and jazz, and I'm very much more inclined to buy these at the higher bit rate. Maximum PC concluded that the lack of DRM and not audio quality is the most important aspect of iTunes Plus (though they don't think it's worth 30 cents a track). So, dear TUAW readers, what do you think? Can you hear the difference between 128 and 256kbps AAC?

[via uneasy silence]