Most mp3 decks will be about the same. I have the JVC KD-SH99, which in my opinion is the best bang for the buck. Remote, motorized face, extended warranty, 24-bit D/A convertor, CD Text and ID3 Tag reader.
The Sony deck (MP450??) is probably decent, but it's butt ugly and not nearly as functional as the JVC.
Honkeytonk posted a pic of the Alpine CDA-7878 which is a great unit if you can afford it. They've put in some kind of circuitry which attempts to replace the missing audio data in MP3 files. Apparently, it sounds really good, but you're paying for it. And since our cars are not exactly air-tight, you don't need 100% super sound if you can settle for computer quality mp3 sound.
I'd really consider the JVC. It might be pricier than some, but it seems to be worth it.
Brian