I backed up my whole CD collection using the ALAC format and figured that if I ever got a different player (I use iPod and iPhone) or music manager ( I use iTunes right now) I could just convert the ALAC's to FLAC's. But before I just run with that, I was wondering if anyone has ever experienced quality loss after the conversion? I appreciate any feed back you might have.

No need to worry. Lossless is lossless.

You'd have to use bad settings or broken software for it to go wrong.
Same as changing the compression format of a text file from ZIP to RAR.