Let's start off with some bad information being corrected:
First, MiniDiscs are NOT stored in MP3 format. They do use ATRAC compression, which like MP3 is LOSSY, but unlike MP3, it uses a much more sophisticated algorithm using phsycoacoustic principles and theories to "make intelligent decisions on what can and can NOT or should not be removed". MP3 just EQ's the snot out of it and then starts dropping bits like at a sex orgy at the leper colony.
Yeah, lovely picture isn't it?
Puh-LEASE!! I worked closely with the development teams on this one, so don't even! Whoever told you that was full of crap.
Tell you what, do this: Involve yourself in recording project from BEGINNING(as in the song writing phase) all the way through the demo and then ultimately studio recording process, then mixdown, mastering and finally duplication. Now you KNOW what it's supposed to sound like.
Take that same CD, rip it to 192K MP3's and it's gonna make it sound boxy. If you can't hear it, then you either lack good ears AND/or good gear. Don't take this as a slam, but when you use high resolution everything all the time, your ear gets trained to it and knows what to listen for. But you've got to invest the time into it, as well as the gear into it(and hence the money).
Then, if you really want to get nasty, re-import the MASTER/CD back into ProTools(becaues that's what I prefer) then also do the same thing with that ripped 192K MP3: It's NOT gonna look the same. Similar yes, but not same. Sit side by side with the mastering engineer on his system and take a listen. Done that yet? I have.
(hell, got the same rig as one of the mastering engineers I use, mainly to do sanity checks on those masters. I can't match his environment though. Same ProTools, same CPU, same hardware, same amp, same speakers, same brand and length of cables because it worked, same connectors, same everything)
Why don't you get complaints? Well, let's sum it up: people don't know good quality until they hear it, and since they can't reference back to compare, they just say "well, I can hear it, who gives a rat's hindparts after that". Plus, people are becoming more and more accustomed to hearing garbage. Equally alarming is environmentally-caused hearing damage and loss on the rise. People are just purposely engaging in actvities that are destroying their ears, be it by choice or even by trade. People don't know what quality is anymore. Plus, most people see a DJ, their expectations are already low anyways. Just how it goes.
Now, I do agree that if you just want to go ghetto, Windows Media Player or even Apple's iTunes player works just fine for background music. Honestly, I think Windows Media Player works a bit better on the drag and drop, as iTunes always wants to fondle the bits a bit for no valid reason.
In the end, MP3 still sounds like ass. Period. CD sounds better. Take "correctly" and even "legally" out and just assume that the MP3 is being ENCODED by the mastering engineer, and it's STILL not going to sound as good as the CD. Closer, close, but NOT quite.
Sorry, but when you deal with someone like me who has a background in both studio engineering and live sound, that ain't gonna fly.
Right now I'm ripping my entire CD library to 16-bit PCM .wav files to my hard drive, which while isn't native to the CD format, it is capable of a direct 1:1 rip/transfer so it is capable of making an exact replica. And I'm also seeing and hearing how many do not make an exact duplicate, as I ran into one that chose to throw some 4:1 hard knee compression on the rip as opposed to just "taking what is there and putting on the drive". I hate it when it sounds all pumpy.
I laughed so hard when you said that MiniDiscs store in MP3 format, I think a piece of calamari I was eating flew out my nose. Thank goodness it wasn't a tube piece!