What is the quality of discs burned from itunes?

Depends on how they're stored on your computer. If you took them from CDs and saved them as AIFF or WAV or ALE files, the quality should be comparable to the original CD. If you converted them to MP3 or AAC (or downloaded them from the Web in one of those formats) then the CD will only be as good as those formats at whatever compression level you used.

I have had pretty good results with the iTunes burner over the Roxie CD Creator that came with my Dell PC. I have been told that EAC (Exact Audio Copy) is the way to go but I have not had a chance to run it and compare yet.

Happy Listening

The iTunes may be mp3 format. If so, they have lost some quality, mostly in the high frequencies. You may not notice much. The mp3 format is a compressed wav file. Data is lost in this compression.

The EAC that bigkidz mentioned is for extracting wav files from a CD. In the extracting, or ripping, the cdrom reader does not always do a perfect job. The EAC software does the best job of correcting this.

CDs ripped into iTunes with "Apple Lossless" and then burnt on to CD sound remarkably brilliant. Don't know about stuff from the iTunes music store, though.