Except the one printed number is 10x larger than the other, there will be absolutely no visual difference at all.
The qouted number is something called Dynamic Contrast. They achieved this by adjusting the backlight brighter or dimmer according to the scene.
If the screen is mostly dark areas like a horror game. Then the backlight would be turned down. Naturally all the blacks would look blacker but unfortunately the difference (or contrast) between each shade remains the same since the entire screen is dimmed by the same amount.
Intead you might find this feature annoying since you are still playing a video game, who in the right mind would lower brightness and decrease visibility of the screen when trying to shoot zombies in the latest a horror game.
It also does the opposite, when in scenes of bright whites, the monitor would adjust them to blinding whites instead.
Static Contrast is where it counts. How much light each pixel can effectively block out. When playing games or watching movies, you would come across very dark scenes but sometimes they have very poor visibility since everything looks like the same shade of black. One way to fix this is to increase gamma of the screen. You would be able to see things but instead of black, everything looks grey. However a high Static Contrast screen on the otherhand can show different tones of blacks and greys very vividly even with low brightness. Dynamic Contrast doesn't do anything to improve visibility of dark scenes.
Probably more than 99% of LCD monitors have 1000:1 contrast spec. I can personally name like VA panels with 3000:1 static contrast, otherwise anything would be 1000:1 or lower, mostly lower.
If you want contrast, I would go for a BenQ EW2420.