MP4 versus MP3 - iTunes SONG QUALITY??

Sorry, but the record companies do not allow the iTunes Store to sell tracks in an uncompressed format. In fact, most download stores are now allowed to sell uncompressed tracks; the only one I know of that does, Music Giants, has much more restrictive copy protection (for instance, you can't burn a track to an audio CD) and won't work on a Mac. Unless and until the record companies come around, the only way for you to get uncompressed tracks is to buy the CD and import the tracks yourself.

This is a good reason that, unless it's a new release, it's a great idea to look for used CDs.
In terms of quality, mp4 is still a lossy format. It wouldn't make much sense for the compressed file to be the same size roughly as aiff. iTunes does have the iTunes plus setting, but you can buy ALL mp3s from Amazon at at least 256k variable. Personally, when I upload, I do so from CDs as much as possible and do it at 320khz.

I got this Michael Jackson CD and all the tracks were 40 megabyte .aif and I had a moment where I realized that mp3's suck in comparison. So now I got this 4 megabyte mp4 file, I was hoping for 40 megs or something

If you already have it in 40MB AIFF, why would you want a 40MB mp4?

A 4MB mp4 will sound pretty good when compared with 40MB aiff.

As much as I love iTunes' selection, their sound quality is pretty bad, and is pretty much as bad as you can get and still remain listenable, aside from myspace/webrips. Almost all of their files are at 128 kbps, whereas I would usually not choose to rip a CD at anything less than 224 kbps.

That said, unless you're using high-end equipment or really have a good ear for music, you might not be able to tell a huge difference.

iTunes Plus songs are 256 kbps.

Ah yes, you're right. I guess I was just under the assumption that the original poster got their song from the normal iTunes store, which has a larger selection and is at 128.

As I said, almost all their files are in 128, with some few exceptions. 🙂

but I'm still getting 128kb, and nowhere do I see the words ITunesPlus

You won't see the words in the store labeling a track. iTunes Plus tracks are indicated by the - wait for it - "+" symbol next to the track. Not all tracks are available in iTunes Plus format; most record companies have not allowed Apple to sell the company's content without copy protection. Only EMI and some independent labels have at of this date allowed iTunes Plus for their content.

What is the format most cd's are in? Aif?

Actually they're PCM. AIFF is the format Apple uses in Mac OS X for uncompressed audio.

I read mp3's are a tenth the quality of aif

It depends on the level of compression used for the MP3. This applies to any compression format that discards data to get the level of compression the user sets, including AAC, WMA, and many others.

where's the customer service. Who handles returns and problems.

iTunes Store Customer Service