Red isn't brigther, unless the LED just puts out more light that they are using. Red will save your night vision more, but won't appear as bright.
Cyan (more of a blue than green cyan) will give you good contrast and "color" rendition at night, and will appear very bright to your eyes.
As far as brightness of amber and artifacts in the beam, it depends on the LED they use. The old Infinities were kind of dim, so a peak would probably be brighter, and may not have the swirly beam either depending on the kind of LED they use..
Amber will be less hard on your night vision than cyan, and have good contrast and focus on things. It won't appear as bright, but will be brighter than Red to your eyes.