Half a year ago I couldn't hear a difference between 192kbps and 320kbps mp3. But I had bad equipment back then. Now my Benchmark DAC-1 is the weakest part of the chain.
I have had 'The Lord Of The Rings - The Return Of The King' as my reference album for half a year and listened to it over 100 times. I never expected I would hear a difference between 320kbps and WAV so I never bought the CD...until now, I bought the 3-disc set trilogy just to get the 2 first albums.
WOW, I didn't expect a night and day difference, the transparence is almost scary, but it doesn't sound as natural as the mp3, the mp3 is more smoother while the WAV is more harsh and bright, but more detailed and transparent. I enjoy 320kbps mp3 more than WAV because it has a smoother sound. This is because my system is too neutral and bright.
After I upgraded my stock power cords to Nordost Vishnu I got extra smoothness in all my mp3 files, maybe the Vishnu's gave a little more transparence to hear the smoothness of mp3?
The first impression of a new upgrade is the most important, after a while I don't hear as big of a difference anymore when I do A/B-ing.
a compressed file may sound "smoothed" to some, to others it will sound "smooshed." some would call it "forgiving" others would call it "inaccurate." but if your preference is for lossy, then go for it! as long as it's high enough where you don't hear any annoying artifacts!