Q:

Laptop matrix parameters like wide color gamut, white variation, haze?

I am not sure I truly understand what these specs mean for a laptop LCD matrix:

Wide color gamut
White variation
"Haze" 44%

Which values are better when picking a screen?

A:

Here is a simplified explanation of each specification and their effect:
Wide Color Gamut (WCG): This simply is a qualitative measure of the number of colors the LCD display can use as opposed to the standard Rec.709 gamut. This generally means more vibrant colors, as opposed to a standard display. This is because:

The color palette itself bigger.
It uses a higher bit depth (8bit, 10bit, etc.), which signifies how many steps of each color a TV has available.

You should use a LCD display with a WCG for a better picture and color fidelity. If this isn't necessary then go for a standard Rec.709 gamut. 
White variation: It is the difference in luminance of the LCD at different spots of the LCD screen. Refer to this note:

Thus, a higher white variation means difference in the white brightness in individual spots of a fixed viewing angle. This should be the lowest possible for visual accuracy. 
Haze: This refers to Reflective Haze. Haze is the measure of how much reflections are diffused.  A higher haze rating usually means an anti-glare coating which is increasingly matte. This generally makes colors less pop out, but with a decrease in reflections. 
Here is a comparison picture of different levels of haze and the effects on reflections and color: 

Generally, under high ambient light, a higher haze is better for increased readability and visual acuity. If there is little chance of reflections or no ambient light is needed, then the haze percentage doesn't need a higher than 25%, which increases apparent color accuracy. 

