Cause Sony sucks! I work for Circuit City and of all the brands they carry Sony is probably the worst, other than maybe AIWA and whatever super cheap ghetto crappy brands they car (like Jensen Road Gear and Qwestar). Kenwood is probably the best budget brand. Pioneer and Clarion are kind of in the middle as far as price goes. Alpine and Eclipse are higher up price wise and most say they have better SQ then all the rest. $300-$400 you can easily find a good brand with something to fit your budget (you may want to check Clarion's new models for this year, they're pretty damn nice). My most important advice is buy online because retail is a ripoff.
http://www.crutchfield.com/S-v3jNSgU...p?i=500CDA7995
well aparently they no longer sell them
you could check out last years Clarion line at thezeb.com they're having a really good sale (again below ebay prices)