Non-opaque white and black acrylic is cut up to 2mm with pleasing results (good edge quality). Blue acrylic is not working at all. Green, red, orange, yellow are working ok, but sometimes the color pigments are reacting chemically and cause bubbles. This is not a color specific issue, it is dependent on the manufacturer.

Laser cutting is a thermal process - this means the energy of the laser light needs to be absorbed by the material. The amount of absorbed energy is the amount of light which is not reflected by the material and is not passing through a (semi-)transparent material. 

Example: A mirror is reflecting 100% of the laser light, a piece of clear acrylic is passing 100% of the laser light. The colors we perceive are the wavelengths a material reflects. Black objects, for example, reflect almost no light, blue objects reflect only light in the spectrum 440-470nm. All other light in the visible spectrum is absorbed.

We have a blue laser beam, this means blue objects reflect the laser light best, while black objects absorb it best. Additionally, colors complementary to blue in the color circle (yellow, orange, red) absorb all the blue light.  The more blue light is absorbed, the better our laser cutter works.