Ghosting depends on how your brain processes the images that your eyes transmit to it. Some may see ghosting on a 5ms LCD others may not. The only way to know for sure is to see it. Generally speaking though 6ms or lower should be "good enough."
Both monitors uses a 6-bit panel and not a single one can produce 16.7 million colors. Again, it is a marketing ploy to trick people into thinking that a 6-bit panel is the same as an 8-bit panel. In fact, a 6-bit panel really produces way, way, way lower than 16.2 million colors.
Hopefully you know how exponents work in math and a tad bit of binary. Binary is easy, 0 or 1 (on / off). The "bits" represent how many registers are used to represent a color that is expressed exponentially. A 6-bit monitor can create 2^6 shades of color for 3 different colors; Blue, Green, Red.
2^6 or 2x2x2x2x2x2 = 64. Therefore, a 6-bit panel produces 64 shades of each color. That means 64^3 or 64x64x64 colors can be created. That only works out to 274,625 different colors. So how does the monitor create 16.2 million colors from only 274,625 colors? Easy. It's called dithering which is basically blending of some colors to imitate one of the 16 million other colors that it cannot accurately create. Read this as bad if you are a graphic artist who's job is dependent on producing precise colors for images.
8-bit monitors really can produce 16.7 million colors. Do the math. 8-bit monitors are more expensive and have slower response time. But they can beat a 6-bit monitor in everything else.