This is what i know. Someone can correct me if i am wrong.
These panels are produced by LG. These are the panels rated A-. If these panels were rated A+ companies like Dell or Apple buy them. When a panel is rated A- companies like Crossover or Yamakasi purchase them. They are the EXACT SAME PANELS used in Apple Thunderbolt monitors. Now i dont know what the standart is for having an A+ but these panels dont differ in quality as far as we know.
They are also cheap beacuse they are produced in Korea and there is not a US or any other company out there selling them for profit. You directly buy these monitors from Korea. Look for example few posts above someone mentioned that these are sold in Microcenter but 100$ more expensive.
Also these Yamakazi and other monitors only have Brightness Control and power button. Thats it. The panel has more buttons but they have NO functions. And last but not least these monitors only have a Dual DVI input. No HDMI or anything else. Hence this is a reason why they are cheap as well.
There are models with HDMI and stuff but they cost more.