''Also keep in mind that if you convert your MP3 collection to M4A, you will lose some sound quality in the process.''
That's why it's best to rip your CDs to a lossless format like FLAC, rather than a lossy format like MP3, WMA, M4A, etc.
Get yourself a large hard drive or DVD burner, rip your CDs to lossless, then stick those CDs in a closet somewhere and never touch them again. Later on, when you decide to try out the new lossy flavor of the month, you can use the lossless copies of your music to convert from, rather than using the CDs.
The advantages with this method are:
no unnecessary damage to sound quality,
you won't have to load CDs,
or mess with ID3 tags,
or babysit the conversion process.