The cheaper ones may not show any problems and, like most products, will probably last a fair time and enjoy a fault-free existence.
But if they don't - in the case of a flat screen, say they have a dead pixel - then you will not be able to return it. In fact, even on branded flat screens it is acceptable (by the industry at large and by the consumer standards authority I believe) for a screen to have up to EIGHT dead pixels before it can be returned under warranty. Unless they are clustered in the centre of the screen.
Due to high demand for flat screens, much of the stock that does not match strict quality controls will still make it to market. The cheaper you go, the more likely you will have a dead pixel develop early in the life of the monitor. Having a discoloured dot on the screen is no fun and even one is noticeable.
The XIOD name is Samsung and is quite good. Acer also do good flat screens for reasonable prices. Initial research of CTX indicates they are a quality manufacturer. They guarantee their 530 model is dead pixel-free.
If buying a flat screen, Insist on opening it up at the shop and viewing it in action (with a single-colour background) if possible. Any dead pixels will be clear to see.