Quality of the LCD monitor will be visible after some time of usage. Here I will give some tips to test the quality of the LCD monitor.
In an LCD monitor is not rare that there are dead-pixels. Dead pixel is a defective form of dots of one color that appears on the screen when turned on. Generally found on large monitors. A good LCD would have a little dead-pixel.
To check for dead-pixels on LCD monitors, open the Internet Explorer, then on the URL line type about:blank and press enter, so you do not need to be online. After that, press F11 to make it appear full-screen.
Check the black dots are not dust or dirt on the screen. If there is, that's dead-pixels. So just throw that proved the LCD monitor contains a lot of dead-pixels. To restore the size of the screen, retype the F11.