Samsung doesn't even compare with NEC, the two companies make different monitors.
LCD monitors comes in two flavors.
TN panel - A cheaper technology but has advantage with response time. 2ms is now typical and manufacturers are making 1ms panels. Also comes in 120hz flavor. Lacks color since TN panels can only display 256k colors and must use dithering or FRC to mimick colors it can't display.
IPS or VA - More expensive panel technology but you get way better color as monitors using either technology would be able to naturally produce 16.7 million color. Can also produce way higher color accuracy and saturation. Way larger viewing angle, you won't see any color distortion around the edges of the monitor for screens below 30". Lacks response time, 5ms - 6ms is typical but thats still very good. Doesn't come in 120hz flavor so if you want 3D these screens are out of contention.
It all comes down to picture quality or speed. I personally went for an LG IPS panel. A 24" IPS screen would be from either NEC or Dell both are good brands and sell pretty much the same thing.
The only thing TN is good for is 120hz. You might want to get one of those since it would provide a bit smoother movement in first person games if your graphics card is up to it that is. All 120hz monitors are basically the same with minor differences. The viewsonic ones suck in terms of color, like TN panels weren't bad enough with color. Im not sure if they make 24" 120hz monitors, i think only 23" but those would be 1080P.