I believe this video adequately makes the case for why my team uses infrared for the retro illuminator.
This video is shot in our workshop under normal lighting conditions. The thin grey lines in the video are the overhead fluorescent lights. The camera is a PS3 eye cam, capturing 320x240 @ 125fps with gain set to 0. It has been modified by replacing the OEM lens assembly with one including an IR-pass, visible block filter and 4.3mm, 70deg FOV lens. The illuminator in is a single 2W 850nm IR Led on a standard star heatsink/pcb.
http://www.youtube.com/watch?v=HzzN5bDGuBc
Raw Video:
https://drive.google.com/file/d/0B4u...it?usp=sharing