I've got basses with red, blue and aqua LED's, the aqua and blue are best, the aqua being the most visible under any conditions, if anything the red ones get lost under various coloured lights.
However, I have recently had a problem whereby I wanted just blue side edge LED's, not front LED's as I have on my other basses. Unfortunately, SIMS will only offer red and amber LEDs for side only retrofits, if you want any other colours you have to have front face LEDs, making the side LEDs fibre optic channels running from the front LED. At least that is what I was told by Martin Sims.
Cheers,
Mike