CD ripping

Melco sounds interesting.  Had not heard of them. 

M4A is lossy compression meaning some information used to create the music is lost in the interest of smaller file size.

These may still sound fine or good enough but for best sound quality possible re-rip is needed to a lossless format.

Compression is fine as long as it is lossless as is typically the case with FLAC format. That is what I use. It provides a lossless format with smaller files that also has good ability to allow files be tagged with other relevant information that can be used to make for a richer user experience (depending on software used to stream and its ability to leverage the tags/metadata). The best of everything in essence.

I rip to flac using dbpoweramp which is a very good tool for assuring best quality results both in terms of sound quality and automatic tagging during the rip process.

WAV format is also lossless and closest to the format used on a CD. Problem is files are bigger and tagging ability limited.

I started with .wav and moved to FLAC. With good quality software used to stream either should sound similarly good in the end.  It did for me.

Good luck.

dbpoweramp can help guarantee 100% accurate rip if possible.

Poor quality or dirty CDs will result in taking longer to rip but if accurate rip is on the results will be the same each time.

It should not matter in the end for rip quality (as opposed to possibly playing live) but you could rip before and then after treatment to see if CD rips faster or not. If treatment helps rip will occur faster. If not the same. Or possibly longer if it actually hurts.

But you would know for sure if you care.

Accurate rip can be turned on or off to enable rips of defective CDs if needed.

Also if you do need other formats of existing lossless files you could look at using a batch conversion program to create the files in an alternate format. that would be much faster than re-ripping

No need to re-rip probably if the lossless variant of the format has been used and the format works for all your devices needed.