Yeah, the quality is the same on the S.O.A.D. song. But I also bought "Holiday" by Green Day from the music store. Converted that to .MP3 and the quality was destorted. When Tre Cool would do punches on the cynbals, the sound drained out. After a few seconds it was back to normal.
I've had similar experiences with AAC files; and there are a number of free/shareware converters out there. However, some of the programs hang up in the process due to a confusion in the DRM (Digital Rights Management) encryption microsoft throws in there. Instead, try the tips from this link (albeit a bit dated); it's always seemed to work for me in the past.
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